He

(a)  

Li

(a)  

B

(a)  

C

(a)  

N

(a)  

O

(a)  

F

(a)  

Ne

(a)  

Na

(a)  

Mg

(a)  

Al

(a)  

Si

(a)  

P

(a)  

S

(a)  

Cl

(a)  

Ar

(a)  

K

(a)  

Ca

(a)  

Ti

(a)  

Mn

(a)  

Fe

(a)  

Co

(a)  

Ni

(a)  

Cu

(a)  

Zn

(a)  

As

(a)  

Se

(a)  

Br

(a)  

Ag

(a)  

Cd

(a)  

Sn

(a)  

Sb

(a)  

I

(a)  

Ba

(a)  

W

(a)  

Os

(a)  

Pt

(a)  

Au

(a)  

Hg

(a)  

Pb

(a)  

Bi

(a)  

Cs

(a)  

Rn

(a)  

Cr

(a)  

Xe

(a)  

Kr

(a)  

Pd

(a)  

Sr

(a)  

Zr

(a)  

Hydrogen

(a)  

Helium

(a)  

Lithium

(a)  

Boron

(a)  

Carbon

(a)  

Nitrogen

(a)  

Oxygen

(a)  

Fluorine

(a)  

Neon

(a)  

Sodium

(a)  

Magnesium

(a)  

Aluminum

(a)  

Silicon

(a)  

Phosphorus

(a)  

Sulfur

(a)  

Chlorine

(a)  

Argon

(a)  

Potassium

(a)  

Calcium

(a)  

Titanium

(a)  

Manganese

(a)  

Iron

(a)  

Cobalt

(a)  

Nickel

(a)  

Copper

(a)  

Zinc

(a)  

Arsenic

(a)  

Selenium

(a)  

Bromine

(a)  

Silver

(a)  

Cadmium

(a)  

Tin

(a)  

Antimony

(a)  

Iodine

(a)  

Barium

(a)  

Tungsten

(a)  

Osmium

(a)  

Platinum

(a)  

Gold

(a)  

Mercury

(a)  

Lead

(a)  

Bismuth

(a)  

Caesium

(a)  

Radon

(a)  

Chronium

(a)  

Xenon

(a)  

Krypton

(a)  

Palladium

(a)  

Strontium

(a)  

Zirconium

(a)