Chemistry 9th Chap 5 : Topic 12 - Maryam Publications

Chemistry Chapter 5 : Topic 12

Bond Formation Diagrams

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A student draws the formation of NaCl using a dot-and-cross diagram. Which statement best explains what happens during bond formation?

A) Chlorine transfers one electron to sodium forming neutral atoms

B) Sodium shares one electron with chlorine to form a covalent bond

C) Both sodium and chlorine share two electrons equally

D) Sodium transfers one electron to chlorine forming oppositely charged ions

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In the formation of MgCl₂, why are two chlorine atoms required for one magnesium atom?

A) Magnesium shares two electrons with one chlorine atom

B) Magnesium loses two electrons and each chlorine atom gains two electrons

C) Magnesium needs two electrons to complete its shell and each chlorine provides one electron

D) Chlorine atoms combine first and then attach to magnesium

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Which dot-and-cross representation correctly shows H₂ molecule formation?

A) Hydrogen atoms form ionic charges

B) One hydrogen loses electron and other gains it

C) Two hydrogen atoms transfer electrons completely

D) Two hydrogen atoms share a pair of electrons

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Why does O₂ form a double bond in Lewis structure?

A) Oxygen forms ionic bond due to charge difference

B) Oxygen atoms transfer electrons completely

C) Oxygen atoms do not follow octet rule

D) Each oxygen shares two electrons forming two shared pairs

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Which best explains bonding in NaF ?

A) Sodium transfers electron to fluorine forming ions

B) Sodium and fluorine share electrons equally

C) Fluorine loses electron to sodium

D) Both atoms become neutral after bonding

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In CaCl₂ formation, calcium becomes Ca²⁺ because:

A) It shares two electrons

B) It gains two electrons

C) It forms two covalent bonds

D) It loses two valence electrons

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Which molecule shows a triple covalent bond in its Lewis structure?

A) H₂O

B) H₂

C) N₂

D) Cl₂

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What is the correct reason CH₄ (methane) forms covalent bonds instead of ionic bonds?

A) Carbon prefers to lose 4 electrons.

B) Methane contains metal atoms.

C) Carbon shares electrons to complete its octet without forming ions.

D) Hydrogen can accept 4 electrons.

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Which statement correctly describes H₂O bonding?

A) Oxygen becomes positively charged.

B) Oxygen shares electrons with two hydrogen atoms.

C) Hydrogen atoms form ionic bonds with oxygen.

D) Oxygen transfers electrons to hydrogen.

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Why is HCl a polar covalent molecule?

A) Electrons are equally shared.

B) Hydrogen becomes negatively charged.

C) Electron density is shifted toward chlorine.

D) Chlorine completely takes electron.

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Which condition leads to ionic bond formation?

A) Two non-metals sharing electrons.

B) Metal transferring electrons to non-metal.

C) Non-metals forming triple bonds.

D) Two metals sharing electrons.

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In CO₂, carbon forms double bonds with oxygen because:

A) Carbon gains electrons.

B) CO₂ is ionic in nature.

C) Carbon shares two electron pairs with each oxygen.

D) Oxygen loses electrons.

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Which molecule has only single covalent bonds?

A) CO₂

B) CH₄

C) O₂

D) N₂

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In HCN, the bond between carbon and nitrogen is:

A) Single bond

B) Double bond

C) Ionic bond

D) Triple bond

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Why do noble gases not form bonds easily?

A) They have no electrons

B) They are metals

C) They already have complete outer shells

D) They always form ionic bonds

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Which statement about CH₃OH (methanol) is correct?

A) It contains both C-H and O-H covalent bonds.

B) It contains only ionic bonds.

C) It contains no hydrogen bonding at all.

D) It is fully metallic.

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What is the main feature of dot-and-cross diagrams?

A) Show only atomic numbers

B) Show movement of protons

C) Show valence electron transfer / sharing

D) Show boiling points

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Why is CaCl₂ electrically neutral overall?

A) Positive and negative charges balance each other

B) Both ions are neutral atoms

C) Calcium becomes neutral again

D) Electrons disappear after bonding

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Which molecule has a linear shape due to bonding structure?

A) H₂O

B) CO₂

C) NH₃

D) CH₄

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Why does NH₃ form covalent bonds instead of ionic bonds?

A) Nitrogen is a metal

B) Nitrogen shares electrons to complete octet

C) Hydrogen loses electrons easily

D) Ammonia contains ions initially

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In ionic bonding, what holds ions together?

A) Shared electron pairs

B) Gravitational force

C) Electrostatic attraction between opposite charges

D) Nuclear force

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Which pair correctly represents a covalent bond only?

A) KBr, HCl

B) NaCl, CaCl₂

C) H₂, CH₄

D) MgO, NaF

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What is the key difference between ionic and covalent bonding?

A) Ionic involves transfer, covalent involves sharing

B) Both involve sharing electrons

C) Ionic involves sharing, covalent involves transfer

D) Both involve metal atoms only

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Why is CH₄ stable despite carbon having four valence electrons?

A) It gains electrons from hydrogen

B) It loses all electrons

C) It shares electrons forming four covalent bonds

D) It becomes ionic

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Which best describes Lewis structure?

A) Arrangement of atoms only

B) Nucleus structure diagram

C) Atomic mass diagram

D) Representation of valence electrons in bonding

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