### Atomic Structure and Bonding Question 2

1. Chlorine has two types of atoms as shown, 35Cl and 37Cl.i. State the name given to the two types of chlorine atoms shown. ii. Calculate the number of neutrons in 35Cl. 
2. Chlorine reacts with sodium to form sodium chloride (NaCl).i. Name the type of bonding in sodium chloride. ii. Draw the dot and cross diagram to show the bonding in sodium chloride. 
3. State any two physical properties of sodium chloride. 
4. Bromine exists as diatomic molecules, Br2. Bromine molecules react with magnesium atoms to form magnesium bromide.State the type of chemical bonding in bromine molecules. 
5. The formula of magnesium bromide is MgBr2. Explain what is meant by this formula. 

### Solution 2

1. i. 35Cl and 37Cl are called isotopes.

Isotopes are atoms of the same element but with different mass numbers. For example, 35Cl and 37Cl have the same proton number (17) but different mass numbers (35 and 37 respectively).

ii. Number of neutrons = nucleon number – proton number

= 35 – 17

= 18

2. i. Ionic bond

Ionic bond is formed when a metal (sodium in this case) loses electrons to the non-metal (chlorine in this case). The positively charged ions formed when the metal loses electrons are then attracted by a strong electrostatic force to the negatively charged non-metallic ions to form a ionic compound (sodium chloride in this case).

ii. 1. Solid at room temperature
2. White in colour
3. Covalent bond

Bromine is a non-metal, so its atoms are bonded together by covalent bonds to form diatomic molecules, Br2.

4. The formula MgBr2 means that one atom of magnesium is bonded to two atoms of bromine.

#### Sydney Chako

Mathematics, Chemistry and Physics teacher at Sytech Learning Academy. From Junior Secondary School to Tertiary Level Engineering Mathematics and Engineering Science.