806. ClF3 exhibits a strong suffocating pungent odor and varies from colorless. When drawing a dot-and-cross diagram for an ionic compound it is usually acceptable to draw the outer electron shell of the metal ion without any electrons. show all your working. The boron atom shares its three valence electrons with three fluorine atoms. 1. Hybridization of NF3 is Sp³. The electronic configuration of beryllium is [He] 2s2and chlorine is [Ne] 3s23p5. The formula is H 2 O so the dot and cross diagram includes two H atoms and one O atom. Draw the displayed formulae of the products formed in part a. There are four oxygen atoms in SO 42- ion, Therefore. BBr3 is nonpolar and has Sp 2 hybridization. Lewis Structure of Borane (BH. Each atom usually makes enough covalent bonds to fill its outer shell. 1. Now, each H atom has two electrons, and N has eight electrons in its outer shell. For the CH4 structure use the periodic table to find the total number of vale. Draw dot-and-cross diagrams to show the bonding in the molecules of NO2 and O3. The BF3 molecule exhibits a ‘Trigonal Planar’ geometry. Draw the dot-and-cross structure of NH3BF3. There are three bonding pairs (electron area in a bond); these will spread the maximum distance apart - that is at an angle of 120. (2 marks for. A step-by-step explanation of how to draw the NF3 Lewis Dot Structure (Nitrogen trifluoride). The hybridization of boron in BF 3 is sp 2. SF4 or sulfur tetrafluoride is a compound that has a distinct odor of sulfur or rotten eggs. 12. The number of electrons on the valence shell of Be and. H has 1 outer electron. (b) Draw a diagram of the ammonia molecule, clearly showing its shape. Dot and cross diagram. Boron trifluoride is a boron fluoride. Nitrogen trifluoride or NF3 is a nitrogen halide compound that is slightly water-soluble. 3 . So, to understand chemical bonding, only sketching a lewis structure diagram is not sufficient. 1: Lewis Electron-Dot Diagrams 3. Each oxygen atom in the pair will share two of their electrons, meaning. Structural diagrams can be used to illustrate covalent bonding. 10 Dot-and-cross diagrams for a boron trifluoride, BF3, andb sulfur hexafluoride, SFg. A step-by-step explanation of how to draw the Br2 Lewis Dot Structure (Bromine gas). Step 6: Place Electrons Around Outside Atoms. A step-by-step explanation of how to draw the CCl4 Lewis Dot Structure (Carbon tetrachloride). 10 Dot-and-cross diagrams for a boron trifluoride, BF3, and b sulfur hexafluoride, SF6. A step-by-step explanation of how to draw the MgO Lewis Dot Structure. . Worked example: Lewis diagram of formaldehyde (CH₂O) Worked example: Lewis diagram of the cyanide ion (CN⁻) Worked example: Lewis diagram of xenon difluoride (XeF₂) Exceptions to the octet rule. The Dot cross diagram is a diagram used to show the outer shell electrons in orbitals around an atom or compound. Therefore, 2s orbital has a 1 ' symmetry +p-orbital: has 3 orbitals , p x, p y, p z. 2. Boron trifluoride is a boron fluoride. The number of the valence electrons in Al is 3 and in Cl, it is 7. A step-by-step explanation of how to draw the NF3 Lewis Dot Structure (Nitrogen trifluoride). Draw a dot and cross diagram to show the covalent bonding in a molecule of ammonia, NH₃. It is an interhalogen compound. BF3 NF3 ClF3. The electrons from one atom are shown as. 2, repulsions are minimized by placing the groups in the corners of a tetrahedron with bond angles of 109. SO2 Lewis Structure. Boron trifluoride is electron deficient The octet rule does not apply Boron is the central atom Actual # valence electrons = (3 x 7) + 3 = 24 Maximum #. A lewis structure helps us to know how electrons are arranged around individual atoms in a molecule. The reaction. (2 marks for. When phosphinePH3combines with hydrogen ionHto form the ionPH4 The hydrogen ionis electron deficient Ithas space for two electrons in its shell The phosphorus atom in. The compound Phosphorous Trihydride (PH3), also known as phosphine consists of phosphorus and hydrogen atoms. The hybridization number of CF4 is Sp³ and the steric number is 4. Using Lewis symbols and Lewis structures, diagram the formation of BF3 from B and F atoms, showing valence-shell electrons. In 1916, Gilbert Lewis Newton introduced a simple way to show the bonding between atoms in a molecule though Lewis electron dot diagrams. 95% C29. An interhalogen compound having both Cl and F, it has a density of around 3. 8 and 0. 1. 75X10+5 mm Hg at 25 °C indicates tetrafluoromethane will exist solely as a gas in the atmosphere. State the new H–N–H and F–B–F bond angles. A three-step approach for drawing the PCl3 Lewis structure can be used. This tutorial will help you deal with the lewis structure and moleculargeometry for boron trifluoride (BF3). 50%, 8. ’. The antisymmetric BF3 stretching mode of BF3-containing complexes has been shown to be very sensitive to perturbation by complex formation, however [47], therefore it is not surprising that it should also vary significantly on changing the matrix material• The symmetric BF3 stretching vibration, being infrared inactive in the monomer,. Here, the given molecule is BF3. The molecule has enough electrons to form the structure called sulphur (IV) oxide. To sketch the BF3 Lewis structure by following these instructions: Step-1: BF3 Lewis dot Structure by counting valence electrons on the boron atom. . A three-step approach for drawing the BeF2 Lewis structure can be used. In UNIT 3, you have learnt that atoms have different ways of combination to achieve the stable octet electronic structure; two of those ways of combination led to the formation of. (3) 1 (b)€€€€ Name the type of bond formed between N and Al in H3NAlCl3 and explain how this bond is formed. Tetrafluoroborate salts are commonly employed as non-coordinating anions. Covalent bonding forms molecules. For the BF3 structure use the periodic table to find the total number of. There are a few guidelines that are useful: 1. Lewis dot. Boron trifluoride is a colorless gas which is formed by several reactions where a boron compound comes in contact with a fluorinating agent. (b) Draw dot-and cross diagrams (outer shells only) to show the bonding in carbon disulphide (CS2) and hydrogen sulphide (H2S). 002 g/mol and a density of 3. Magnesium loses two electrons and oxygen gains two electrons, leaving Mg 2+ and O 2-. The hybridization of the SiCl4 molecule is Sp 3. Boron trifluoride, BF. 8 and 0. This indicates that the boron (B) and fluorine (F) are chemically bonded with each other in a BF3 molecule. InstructionsNow, let’s learn to draw the Lewis structure of carbon tetrafluoride (CF4) with steps: Step 1: Find the total number of valence electrons each carbon tetrafluoride (CF4) molecule has: It is 32 as 4 are coming from the carbon atom and 7 are coming from each fluorine atom. Guidelines for Drawing Dot Cross Diagram. Let’s see how to draw the lewis structure for CO2 with simple steps. Copy Sheet of paper on top of another sheet. It is also used in the refining of aluminium, magnesium, zinc, and copper alloys to remove nitrides, carbides, and oxides from molten metal. The MO diagrams help in determining the existence of the molecules. (a). NF3 has a molar mass of around 71. These structural diagrams depict only the outer, or valence, shell electrons. All total this molecule has 2 4 valence electrons. Dot and cross diagrams can be used to show the formation of a co-ordinate bond. Swap the crosses for dots in one of your diagrams. Unfortunately, that by itself does not allow you to write the structure; you need to know which element is in the centre and how they are connected. (or electron dot diagram or a Lewis diagram or a Lewis structure) is a representation of the valence electrons of an atom that uses dots around the symbol of the element. The. Formula: BF 3. Question. Water, H2O 2. Count total valence electrons in CO2. The central Br atom is sp 3 d hybridized in BrF 3. Key Points To Consider When Drawing The Br2 Electron Dot Structure. The compound Phosphorous Trihydride (PH3), also known as phosphine consists of phosphorus and hydrogen atoms. Lewis dot structure b. explain the disadvantages of stick diagrams? a covalent bond is shown as a stick so we cannot tell which electron in the bond came from which atom. The number of dots equals the number of valence electrons in the atom. For the Br2 structure use the periodic table to find the total number of. Copy Sheet of paper on top of another sheet. Lewis Structure of CO2. You . Draw a dot and cross diagram to show the covalent bonding in a molecule of ammonia, NH₃. 3D: BF3 B F 3. 44D. The lewis structure of BH 3 contains a total of 3 bond pairs and 0 lone pairs. 5°. electron geometry d. BF3 + BCl 3 → BF2Cl + BCl2F. Include any lone pairs of electrons and the value of the bond angle. A dot and cross diagram shows the transfer of electrons from metal atoms close atom The smallest part of an element that can exist. The H circles must each overlap the O circle. 12K views 1 year ago. Figure 4. (a) State what is meant by the term covalent bond. Step 5: Draw a Skeletal Structure. Provide the following information for the compound BF3. Since its steric number is 3. BF3 is SP2 hybridization. In a dot and cross diagram: Only the outer electrons are shown. 1 4. Example 1. (a) Draw the Lewis structure of the ammonia–boron trifluoride reaction product. TIP. Note the lone pair (dots without bonds) on top of P, just like for N in the previous example for NH 3. The H circles must each overlap the O circle. Step 4: According to the electron-dot structure concept, valence electrons will be placed around the atoms in the molecule via dot notations. . The BF 3 Lewis structure is similar to BCl 3 and BBr 3 since Cl and Br are in Group 7 and have 7 valence electrons. Molecular Geometry. All molecules that has a trigonal planar structure has 120° bond angles. Substances with small molecules have low melting. ii)suggest the shape of the molecule if B is the central atom. “Phosphorus. For the BF3 structure use the periodic table to find the total numb. We use dot and cross diagrams to show which atom the electrons in a covalent bond come from. In this article, we will discuss Phosphorous trifluoride (PF3) lewis structure, molecular geometry or shape, electron geometry, hybridization, polar or nonpolar, its bond angle, etc. . Show the co-ordinate bond by an arrow. As per the NCl3 lewis dot structure, nitrogen is the central atom that has 3 bonded pairs of electrons and one lone present on it. 12. Therefore, 2p z orbital has a 2" symmetry. I don’t get why. There are two lone pairs of electrons on the Sulphur atom which makes the geometry of the molecule bent. As you can see there are 7 electrons in the outer shell when it is not bonded to anything else. Bromotrifluoromethane was found at concns of 0. The total valence electron available for the NF3 lewis structure is 26. 1 4. Here is the dot and cross diagram for oxygen (O 2), a diatomic molecule. Find the number of electrons in one atom. The antisymmetric BF3 stretching mode of BF3-containing complexes has been shown to be very sensitive to perturbation by complex formation, however [47], therefore it is not surprising that it should also vary significantly on changing the matrix material• The symmetric BF3 stretching vibration, being infrared inactive in the monomer,. CS2 has two S atoms, hence, the valence. 5º. 5*6 -4 = 0. and then mark your new answer with a cross . NF3 Lewis Structure, Molecular Geometry, Hybridization, Polarity, and MO Diagram. The first step is to sketch the Lewis structure of the BeF2 molecule, to add valence electron around the Beryllium atom; the second step is to valence electron to the two fluorine atoms, and the final step is to combine the step1 and step2 to get the BeF2 Lewis Structure. Which dot-and-cross diagram represents the electronic structure of the peroxide anion in BaO2? Q7 In this question, the methyl group, CH3, is represented by Me. Each of the molecules, NH 3 and BF 3, has a different feature of its electronic structure that allows this to happen. If you wish you need only draw the outer shell electrons; (2 marks for each correct diagram) 1. The Intricacies of PO4 3- Lewis Structure A. Show the outer electrons only. When constructing a Lewis diagram, keep in mind the octet rule, which refers to the tendency of atoms to gain, lose, or share. The electrons can be represented by any shape such as a dot, cross, square and many more. 45 g/mol. 12. The Lewis structure for CCl4 is a commonly tested Lewis struc. Lewis Structure is the name given to such a skeletal diagram where we use the symbols of the atoms and use dots to represent the valence shell electrons. Each fluorine atom starts with seven valence electrons and uses only one of them to bond. Using Lewis symbols and Lewis structures, diagram the formation of BF3 from B and F atoms, showing valence-shell electrons. 32 mins. There are three bonding pairs (electron area in a bond); these will spread the maximum distance apart - that is at an angle of 120o. As we know, the lewis diagram is all about representing. PhysicsAndMathsTutor. On the oxygen that has the single bond, there is an extra electron, this is where the negative charge is. 2. The number of dots equals the number of valence electrons in the atom. Dots and crosses are used to represent the electrons. 445 g/mol molecular weight and a density of 4. Draw dot-cross diagrams to show the bonding in the following compounds: a) Ca(OH)2 b) Na2SO4 c) NH4NO3. to non-metal atoms. . 1 4. The molecular geometry or shape of CHCl3 is tetrahedral. Give the definition of a covalent bond. 3 Exercise 3 - molecular shapes 1. The gases NH3 and BF3 form a white solid, NH3BF3, in which every atom has a full outer shell. Follow some steps for drawing the Lewis dot structure for CO2. Sulfuric acid, H 2 SO 4Lewis Dot Structure for BrF3. When ammoniaNH3combines with boron trifluorideBF3to form the compound F3BNH3 The boron trifluorideis electron deficient The boron atom in theboron trifluoride has. In the lewis structure of nitric acid, there is a +1 charge on nitrogen atom and one double bond between nitrogen and one oxygen atom. with empty orbital in BF3 Forming. (2)Construct ‘dot-and-cross’ diagrams to describe ionic bonding. A video explanation of how to draw the Lewis Dot Structure for the Tetrafluoroborate Ion, along with information about the compound including Formal Charges,. {eq}BF_3 {/eq} consists of a boron atom that is single-bonded to three fluorine atoms. Metallic bond. Each carbon is $, ext{sp }$ hybridized and the molecular structure is$ ext{ }{{ ext{C}}_{ ext{2}}}{{ ext{H}}_{2}} ext{ }$. Bromotrifluoromethane is the main source of bromine radicals in the atmosphere above 25 km (3). The worksheet for activity 3 will build on their confidence and understanding. May 22, 2023 by Jay Rana. Chlorine trifluoride has an appearance like a greenish-yellow liquid or colorless gas with a pungent smell. Here are the dot-to-dot cross diagrams and named sketches of the molecular shapes for methane (CH4) and boron trifluoride (BF3), along with their internal angles: Methane (CH4) Dot-to-dot cross diagram:A step-by-step explanation of how to draw the NH3 Lewis Dot Structure (Ammonia). com Video: Drawing the Lewis Structure for BF3. 3 Exercise 1 - dot-cross diagrams 1. Step-2: Lewis Structure of BF3 for counting valence electrons around the terminal fluorine atom. Class 10. 1. 2. lewis structure 22. Draw the possible isomers of the compound with molecular formula C3H6O and also give their electron dot structures. H. Therefore, the number of valence electrons in the Carbon atom =4. In order to obtain eight valence electrons (an octet), the potassium atom will transfer its single valence electron to the fluorine atom. A step-by-step explanation of how to draw the BrF5 Lewis Dot Structure (Bromine pentafluoride). One example is BF3. Draw dot and cross diagrams for ionic compounds. Phosphine does not have any odor when it is pure, but most samples of the gas have the unpleasant odor of rotten garlic or decaying fish. Prolonged exposure of the containers to fire or heat may result in their violent rupturing and rocketing. In the BF 3 Lewis dot structure, a total of 9 lone pairs and 3 bond pairs are present. January 12, 2023 by Jyoti Bashyal. Over- exposure by any route can cause bloody stools, slow pulse rate, low blood pressure, coma, convulsions, and cardiac arrest. The dot structure for sulfur dioxide has sulfur with a double bond to an oxygen on the left, and two lone pairs of electrons on that oxygen, and the sulfur with a double. Exceptions to the octet. From its name it is clear that ethyne has two carbon atoms. Nitrogen gas occurs naturally as a diatomic molecule. . So just draw it out. Here, we have got the most suitable and appropriate Lewis Structure Sketch of ethylene. The electrons present in the outermost shell of an atom are shown in the Lewis structure of any molecule. Each atom usually makes enough covalent bonds to fill its outer shell. The Lewis dot diagram shows the valence electrons of each atom as dots surrounding the atomic symbol. From its name it is clear that ethyne has two carbon atoms. Step-3: Lewis dot Structure for BF3 generated from step-1 and step-2. Think about the number of electrons in the outer orbital of the iodine atom (7) and then the three fluorine atoms forming covalent (sharing electrons) bonds with the iodine atom, then the remaining electrons. (2). 3. The molecular geometry of SOCl2 is trigonal pyramidal and its electron geometry is tetrahedral. 0 dm3 of O, at room temperature and pressure (RTP). . A. During ionic bonding the atoms form ions by gaining or losing electrons to obtain a full outer shell. omg, please explain how to answer these questions, I tried to draw a dot and cross diagram to get me started but I'm stuck again. must. The dot-and-cross diagrams for oxygen, carbon dioxide and ethene, all of which have double. Each atom can get a complete shell if three H atoms share their electrons and form covalent bonds with an N atom. If you wish you need only draw the outer shell electrons; (2 marks for each correct diagram) 1. 2. . Formula: BF 3. 3. Carbon belongs to Group 4 of the periodic table. Sulfuric acid, H2SO4 Bonding 3. Counting valence electrons. Electron Dot Diagram for BF3. as in O2, N2 and CO2 (iii) dative. Super Octet Compounds. 3 Exercise 2 - electronegativity 1. It won't have 10 in the outer orbital. Shared pairs of electrons are drawn as lines between atoms, while lone pairs of electrons are drawn as dots next to atoms. Chemistry of the Nonmetals 2h 1m. 1 Some examples of nonpolar molecules based on molecular geometry (BF 3 and CCl 4 ). must. Lewis dot diagram for (AlCl_3) AlCl 3 , like BF 3 , is electron deficient. Draw the Lewis structure for each one and then describe the electron-pair geometry and the molecular geometry. Strong electrostatic attraction between a shared pair of electrons and two nuclei. Show only the outer electron shells. Original post by NLS. BF3 Lewis Structure. This molecule is flat, that is it lies in a plane; such a molecule is said to be planar. Draw dot-cross diagrams for the following ions: a) SO42- b) CO32- c) SO32- c) OH-19. 2. For this molecule, It is SP2 because one π (pi) bond is required for the double bond between the Boron and only three σ bonds are formed per Boron atom. Phosphorus and bromine Electronegative difference in PBr3: To sketch the PBr3 Lewis structure by following these instructions: Step-1: PBr3 Lewis dot Structure by counting valence electrons on the phosphorus atom. CAMEO Chemicals. The Fluorine and the Boron atoms mutually share their electrons with each other, to fulfil the octet of Fluorine, but Boron's octet is not fulfilled. Each Fluorine atom has 7 valence electrons. Valence Shell Electron Pair Repulsion (VSEPR) theory is a model used to predict the geometry of molecules based on the repulsion between valence shell electr. Transcribed Image Text: Draw dot-and-cross diagrams to show the formation of a co- ordinate bond between the following: 4 a boron trifluoride, BF3, and ammonia, NH3, to form the compound F3BNH3 ii phosphine, PH3, and a hydrogen ion, Ht, to form the ion PH4*. Now, as there are three Fluorine atoms, the electrons in its outer shell will form a bond. As we know, the lewis diagram is all about representing. Draw the VSEPR picture for C H 3 C O 2 . 3 Hydrogen atoms in BH3: (Ligand group. CO 2: H 2 O: Dot and cross diagrams for ionic compounds; can be drawn like this: There is a serious mis-match between this structure and the modern electronic structure of carbon, 1s 2 2s 2 2p x 1 2p y 1. b Draw the displayed formulae of the products formed in part a. A Lewis symbol consists of an elemental symbol surrounded by one dot for each of its valence electrons: Figure 7. Boron trifluoride is a versatile Lewis acid that forms adducts with such Lewis bases as fluoride and ethers : CsF + BF3 → Cs [BF4] O (CH 2 CH 3) 2 + BF3 → BF3·O (CH2CH3)2. A step-by-step explanation of how to draw the BF3 Lewis Dot Structure (Boron trifluoride). Chemistry questions and answers. Dot and cross diagram. Class 9. The VSEPR theory predicts the correct shape based on three groups of bonding electrons and no lone pairs on electrons on the. (2) ii) During this reaction, the bond angles about the nitrogen atom and the boron atom change. Oxygen belongs to group 16 ( or group 6) and has an atomic number of 8, therefore a valency of 6. Follows the below step to determine the Lewis dot structure of the. Boron has 3 valence electrons. . 4. How to draw a dot and cross diagram for ammonia In NH 3, commonly known as ammonia, nitrogen forms three single covalent bonds with three hydrogen atoms. We can see that the three F atoms and the single Br atom all have their formal charge value to be 0. 000: 16. As you can see there are 7 electrons in the outer shell when it is not bonded to anything else. The ionic lattice has a structure in which six chloride ions surround one aluminium ion, in an octahedral arrangement. "Al" and "Cl" must achieve their octets by sharing electrons. Show only the outer electron shells. Prolonged exposure of the containers to fire or heat may result in their violent rupturing and rocketing. NF3 lewis dot structure contains 1 lone pair and 3 bonded pairs. be shown in a dot-and-cross diagram. 3 Exercise 2 - electronegativity 1. Phosphorus trichloride (PCl 3) contains three chlorine atoms and one phosphorus atoms. BF 3 is a trigonal planar molecule and all three peripheral atoms are the same. CH. Draw a dot and cross diagram to show the formation of an ammonium ion, NH4+, by reaction of ammonia, NH3 and a H+ ion. This compound is generally identified as being a colorless gas. Fe + 2HCl -> FeCl2 + H2. 3 ExercisesBoron trichloride is a starting material for the production of elemental boron. Each molecule contains a dative covalent bond, and in the NO2 molecule the central atom is. The first step is to sketch the Lewis structure of the BeF2 molecule, to add valence electron around the Beryllium atom; the second step is to valence electron to the two fluorine atoms, and the final step is to combine the step1 and step2 to get the BeF2 Lewis Structure. For the BrF5 structure use the periodic table to find the tota. The liquid is not soluble in water and is non-combustible. The atom that needs the most electrons to be stable is the central atom. For the Br2 structure use the periodic table to find the total number of. Lewis Structure - II. Chlorine trifluoride (ClF3) Lewis dot structure, molecular geometry or shape, electron geometry, bond angle, formal charge, hybridization. This Elkchemist A-Level short shows how to draw the Lewis structure and represent the Dative bonding in carbon monoxide (CO). (e) Does BF3 obey the octet rule? Verified. The hybridization of boron in BF 3 is sp 2. Here, the given molecule is BF3. Include in your diagrams any lone pairs of electrons that influence the shape. In Lewis Structure, we show the bonds in the structure by drawing a straight line between two atoms. 3. The dot and cross diagram of the molecule with the proposed double bond shows that sharing a second pair of electrons would also mean having to promote two electrons into the next energy level. NH3 (Ammonia) is a commonly tested Lewis structure. Since its steric number is 3. The first step is to sketch the Lewis structure of the PCl3 molecule, to add valence electrons around the phosphorus atom; the second step is to add valence electrons to the three chlorine atoms, and the. 2. The first step is to sketch the Lewis structure of the Br2 molecule, to add valence electrons around the two bromine atoms, and the final step is to combine the two bromine diatomic atoms to get the Br2. Give the definition of a covalent bond. We’re told one of these bonds is a coordinate covalent bond. Each fluorine atom starts with seven valence electrons and uses only one of them to bond. Draw dot and cross diagrams for simple covalent molecules 2 Identify single, double and triple covalent bonds Introduction A covalent bond is a shared pair of electrons. Using Lewis symbols and Lewis structures, diagram the formation of BF3 from B and F atoms, showing valence-shell electrons. 23. Each molecule contains a dative covalent bond, and in the NO2 molecule the central atom is. Duke University. a co-ordinate bond a covalent bond a lone pair CO CO CO [3]To determine the number of lone pairs and bonding pairs of electrons for BF3 we first need to draw as valid Lewis Structure. 7 parts per trillion in monitoring studies conducted over the northern and southern hemisphere of the eastern Pacific Ocean, respectively (2). There are three bonding pairs (electron area in a bond); these will spread the maximum distance apart - that is at an angle of 120o. So the resonance structure on the left, and the resonance structure on the right, and some people disagreed with me, and said that's not the dot structure for sulfur dioxide. Sketch the lewis dot structure of the following molecules. ∴ Total valence electrons available for C2H4 lewis structure = 4*2 + 1*4 = 12 valence electrons [∴ C2H4 has two carbon and 4 hydrogen atom] 2. Sodium is a group 1 metal so will lose one outer electron to another atom to gain a full outer shell of electrons; A positive sodium ion with the charge 1+ is formed; Chlorine is a group 7 non-metal so will need to gain an electron to have a full outer shell of electronsDraw dot and cross diagrams for: • BF3 • PF5 • SO2 • SO3. Then draw the shared electrons inside the overlapping section. Here are the dot-to-dot cross diagrams and named sketches of the molecular shapes for methane (CH4) and boron trifluoride (BF3), along with their internal angles: Methane (CH4) Dot-to-dot cross diagram: A step-by-step explanation of how to draw the NH3 Lewis Dot Structure (Ammonia). Once we have a Lewis Structure f. O has 6 outer electrons. This is the outer shell of chlorine: +. Molecular Geometry of BF3. The bonding in IF is the smae as in the halogen elements. See the following examples for how to draw Lewis dot structures for common atoms involved in covalent bonding. 3.