Introduction to

ATOMS

Electrons are always on the move.

Neutrons and protons are held together in the nucleus by the “strong” force, which has to overcome the electrical repulsion of the positively charged protons.

Electrons are held around the atom by the electrical attraction between their negative charge and the positive charge of the protons in the nucleus.

Protons = positive charge +

Neutrons = neutral charge = no charge

Electrons = negative charge -

+

-

The Periodic Table shows the Symbol, ATOMIC number,

ATOMIC weight, and the name of each ELEMENT.

SYMBOL

ATOMIC NUMBER ATOMIC WEIGHT

NAME

H1

1.008Hydrogen

HYDROGEN

Hydrogen has an Atomic number of 1.

Hydrogen has an Atomic weight of 1.008

The symbol for hydrogen is H.

H1

1.008HYDROGEN

HELIUM

Helium has an Atomic number of 2.

Helium has an Atomic weight of 4.00

The symbol for Helium is He.

He2

4.00HELIUM

LITHIUM

Lithium has an Atomic number of 3.

Lithium has an Atomic weight of 6.94

The symbol for Lithium is Li.

Li3

6.94LITHIUM

BERYLLIUM

Beryllium has an Atomic number of 4.

Beryllium has an Atomic weight of 9.01

The symbol for Beryllium is Be.

Be4

9.01BERYLLIUM

BORON

Boron has an Atomic number of 5.

Boron has an Atomic weight of 10.81

The symbol for Boron is B.

B5

10.81BORON

CARBON

Carbon has an Atomic number of 6.

Carbon has an Atomic weight of 12.01

The symbol for Carbon is C.

C6

12.01CARBON

NITROGEN

Nitrogen has an Atomic number of 7.

Nitrogen has an Atomic weight of 14.01

The symbol for Nitrogen is N.

N7

14.01NITROGEN

OXYGEN

Oxygen has an Atomic number of 8.

Oxygen has an Atomic weight of 16.00

The symbol for Oxygen is O.

O8

16.00OXYGEN

FLUORINE

Fluorine has an Atomic number of 9.

Fluorine has an Atomic weight of 19.00

The symbol for Fluorine is F.

F9

19.00FLUORINE

NEON

Neon has an Atomic number of 10.

Neon has an Atomic weight of 20.18

The symbol for Neon is Ne.

Ne10

20.18NEON

NUCLEUS