All atoms of the same element have the same which can be found on the periodic table ?

If a || b and e || f, what is the value of y ?

The chemical equation below shows the reaction of sodium (na) and chlorine (cl) to form sodium chloride (nacl). 2na + cl2 → 2nacl in this equation, which of the following is a reactant? i. sodium ii. chlorine iii. sodium chloride

What is the work done by the electric force to move a 1 c charge from a to b?