Atomic Structure

The structure of the atom

ELECTRON – negative,

mass nearly nothingPROTON –

positive, same mass as neutron

(“1”)

NEUTRON – neutral,

same mass as proton

(“1”)

The Ancient Greeks used to believe that everything was made up of very small

particles. I did some experiments in 1808 that proved this and called these particles

ATOMS:

Dalton

Mass and atomic numberParticle Relative Mass Relative Charge

Proton 1 1

Neutron 1 0

Electron 0 -1

MASS NUMBER = number of protons + number of neutrons

SYMBOL

PROTON NUMBER = number of protons (obviously)

The Atom

Nucleus Electron

Shell or Orbit

The Atom Hydrogen

Proton Electron

Hydrogen has one proton, one electron and NO neutrons

The Atom Helium

ElectronProton

Neutron

Helium has two electrons, two protons and two neutrons

The Atom Helium

ElectronProton

Neutron

Helium has two electrons, two protons and two neutrons

The Atom Lithium

Protons

Neutrons

Electrons

The Atom Beryllium

Protons

Neutrons

Electrons

Beryllium has four electrons, four protons and five neutrons.

The Atom Boron

Protons

Neutrons

Electrons

Boron has five electrons, five protons and six neutrons.

The Atom Carbon

Protons

Neutrons

Electrons

Carbon has six electrons, six protons and six neutrons.

The Atom Nitrogen

Protons

Neutrons

Electrons

Nitrogen has seven electrons, seven protons and seven neutrons.

The Atom Oxygen

Protons

Neutrons

Electrons

Oxygen has eight electrons, eight protons and eight neutrons.

The Atom Fluorine

Protons

Neutrons

Electrons

Fluorine has nine electrons, nine protons and ten neutrons.

The Atom Neon

Protons

Neutrons

Electrons

Neon has ten electrons, ten protons and ten neutrons.

The Atom Sodium

Protons

Neutrons

Electrons

Sodium has eleven electrons, eleven protons and twelve neutrons.

HELIUM ATOM

+N

N

+-

-

proton

electron

neutron

Shell

What do these particles consist of?

How many protons, neutrons and electrons?

Ionic and Sub Atomic Particles

CATION

+1 lose 1 electron in its outer shell

Ion = atom or group of atoms who gain or lose electron(s)

Number of proton = 11Number of electron = 11 – 1 = 10Number of neutron = 23 – 11 = 12

+2 lose 2 electrons in its outer shell Number of proton = 12Number of electron = 12 – 2 = 10Number of neutron = 24 – 12 = 12

Ionic and Sub Atomic Particles

ANION

-2 gain 2 electron in its outer shell Number of proton = 8

Number of electron = 8 + 2 = 10Number of neutron = 16 – 8 = 8

-1 gain 1 electrons in its outer shell Number of proton = 17

Number of electron = 17 + 1 = 18Number of neutron = 35 – 17 = 18

ISOTOPES

p = 1 n = 0 e = 1 p = 1 n = 1 e = 1 p = 1 n = 2 e = 1

Isotopes = same number of protons different number of neutrons

= same AN; different MN

Hydrogen Deuterium Tritium

ISOBARS

p = 1 n = 2 e = 1 p = 2 n = 1 e = 2

Isobars = same mass number (p + n)

ISOTONES

p = 1 n = 2 e = 1 p = 2 n = 2 e = 2

Isotones = same number of neutrons

K39

19Cl

39

17and

P30

15S

31

16and

1.

2.

N15

7O

17

8and

3.

F19

9Ne

20

10and

4.

B10

5B

11

5and

5.

Ag105

47Cd

106

48and

6.

Determine these following pairs of atoms as isotope, isobar or isotone!

isobar

isotope

isotone

isotone

isotone isotone

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