An object with more mass has more kinetic energy than an object with less mass, if both objects are moving a) at the same speed b) in the same direction c) in opposite directions

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.

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