Covalent bonding

Covalent bonds are usually formed between--------

•     Two nonmetals

• One metal and one non-metal

• Two metals

Answer explanation

Two non-metals

What it is called when atoms share one pair of electrons

• covalent bond

• Ionic bond

• Metallic bond

• Transfer bond

How many covalent bonds can nitrogen form?

• 3

• 2

• 1

• 4

Answer explanation

It has 3 unpaired electrons in its outermost energy level (electron shell) therefore will form 3 covalent bonds

Methane is covalently bonded. How many bonds are involved?

• 1

• 2

• 3

• 4

Answer explanation

The carbon forms one covalent bond with each hydrogen atom, the formula of methane is therefore CH₄

How many electrons are involved in a covalent bond?

• 1

• 2

• 4

• As many as are free

Answer explanation

Covalent bonds are formed from pairs of electrons, one from each atom involved

Which of these has molecules with two atoms joined by a covalent bond?

• Bromine

• methane

• copper

• neon

Answer explanation

Bromine is described as a diatomic molecule

Covalent bonds can be single, double, or triple covalent bonds. How many electrons are shared in each? Give an example of each type.

Answer explanation

A single covalent bond is formed by sharing of one pair of electrons between atoms; each atom contributes one electron. Ex: Formation of Hydrogen molecules

A double bond is formed by sharing two pairs of electrons between two atoms. Ex: Formation of Oxygen molecule

A triple bond is formed by sharing of three pairs of electrons between two atoms. Ex: Formation of N2 molecules

Show number of bonds in

(i) ethene molecule (ii) ethyne molecule

Answer explanation

1)Ethene molecule has one double covalent bond and four single covalent bonds.

i2) Ethyne molecule has one triple covalent bond and two single covalent bonds.

An element A has 1 electron in its first shell. It combines with clement B having 7 electrons in its third shell. What type of bond is formed ?

Answer explanation

Element A with 1 electron in its first shell is hydrogen, and element B with 7 electrons in its third shell is chlorine. So, a single covalent bond is formed between hydrogen and chlorine by sharing one pair of electrons.