Question

4 State the number of electrons lost or gained when the following elements form ions: 

a. O b. Group 2A (2) e. F d. K  e. Rb 

16 Which of the following pairs of elements are likely to form an ionic compound? 

a. helium and oxygen b. magnesium and chlorine c. chlorine and bromine d. potassium and sulfur e. sodium and potassium f. nitrogen and iodine 

20 Write the symbols for the ions, and the correct formula for the ionic compound formed by each of the following: 

a. calcium and chlorine b. rubidium and bromine c. sodium and phosphorus d. magnesium and oxygen

Answer 1

4)

Generally the atoms try gain octate electron configuration for stabilization.

so in case of oxygen electron configuration

a)O 1s² 2s² 2p⁴ if it gain two elections it will get octet rule configuration so the configuration will be O^2- 1s² 2s² 2p6

O + 2e ---> O^2-

b)2A elements have ns² configuration

EX Mg 1s² 2s² 2p6 3s² if it loose two elections it will get octet rule configuration so the configuration will be Mg²⁺ 1s² 2s² 2p6

Mg ----> Mg²⁺ + 2e

M ----> M²⁺ + 2e

M is 2A element

c) for F gain of electron

F + 1e ------> F^-

d) for K loose of electron

K ------> K⁺ + e

d) for Rb loose of electron

Rb ------> Rb⁺ + e

16)

answer ;

In the ionic bond formation the electronegativity difference between the two atoms should more than 1.7

ionic compound

He⁺¹ + O_2- ---> He₂O

Mg²⁺ + Cl₂^2- -----> MgCl₂

remaining all compounds the electronegativity is lower than 1.7.

20)

a) Ca²⁺ + Cl₂^2- ----->CaCl₂

b) Rb⁺ + Br- ----> RbBr

c) 12Na⁺ + P₄^3- --------> 4Na₃P

d) Mg²⁺ + O^2- -----> MgO