Common and easy elelments

Common and not so easy

Difficult

Unusual

H

Ag

Hg

Mt

C

Li

Au

Gd

O

Be

Ti

N

Br

V

F

Ca

Cr

Cl

Na

Ba

I

Ph

Sr

He

K

Ar

S

Ne

Kr

Al

Mg

Xe

Co

Fe

Ni

Cu

Zn