Name one element with similar chemical properties to lithium

Sodium

Explanation:

Its neighbor to the bottom (sodium) has similar properties to lithium. Group trends are very strong for the Group 1 (alkali) and Group 2 (alkaline earths) metals. Group 1 elements behave very similarly to each other.

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).