preriodic table

1. Period

1.1. Rows of elements are called period.

1.1.1. 7 periods

1.1.1.1. Period 1 H~He

1.1.1.2. period2 Li~Ne

1.1.1.3. period3 Na~Ar

1.1.1.4. Period4 K~Kr

1.1.1.5. Period5 Rb~Xe

1.1.1.6. Period6 Cs~Rn

1.1.1.7. Period7 Fr~Uuo

2. Group

2.1. Columns of elements help define element groups

2.1.1. 18 groups

3. nonmetallic element

3.1. gas

3.1.1. H,He, N,O, F, Ne,Cl,Ar,Kr,Xe,Rn.

3.2. Liquid

3.2.1. Br,

3.3. Solid

3.3.1. I,B,C.

4. mentallic element

4.1. liquid

4.1.1. Hg,Fr,Ga,Ru,Cs.

4.2. Solid

4.2.1. Na,Mg, AL,