Identify the true statement(s) about the periodicity in the main-group elements. 1. The metallic character of elements decreases from left to right in any row of the periodic table. 2. The metallic character of elements increases from top to bottom in any column of the periodic table. 3. Elements with high ionization energy tend to be metallic, whereas those with low ionization energy tend to be nonmetallic.

the law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. because atoms are only rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both the reactants and products

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8