An element has a metallic-grey appearance. It also has properties of both a metal and nonmetal. In which section of the periodic table indicated above would the element most likely be found?

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