Explanation:
9/4 Be +2 (the 9 and 4 are stacked next to Be). Atomic #: 4
Mass #: 9, # protons: 4, # neutrons: 5, #electrons: 2.
31/15 P (31 is stacked over 15 next to the P). Atomic #: 15,
Mass #: 31, # protons: 15, # neutrons: 16, # electrons: 15.
Is a solid because liquids are not is not that close and gas is very far apart.
The relation between force and mass and acceleration is

The SI unit will be
Force = Newton
mass =kg
acceleration=
thus

putting values

Thus the acceleration will be

The melting point of potassium = 
Melting point of titanium = 
Titanium has a stronger metallic bonding compared to potassium. Titanium being a transition metal has greater number of valence electrons (4 valence electrons) contributing to the valence electron sea compared to potassium which has only one valence electron. The atomic size of Titanium much lower than that of potassium, so the bonding between Titanium atoms is stronger than that of potassium. Hence, the melting point of Titanium is much higher than that of potassium.