a.

Dissolution of salt in water

b.

Rusting of iron

c.

Melting of ice

d.

Separating a mixture by distillation

a.

s-orbitals

b.

p-orbitals

c.

d-orbitals

d.

f-orbitals

a.

are both metals

b.

belong to the same group

c.

belong to the same period

d.

are positioned diagonally to each other

a.

Collisions are perfectly elastic

b.

Forces of repulsion exist

c.

Forces of repulsion and attraction are in equilibrium

d.

Collisions are inelastic