Friday, September 12

• Element Quiz 1 Today

• Extra Credit Prototype due today

• Element Quiz 2 Thursday

• Atomic Structure Test Friday 19th

Electron Shells (Energy Levels)

Electrons in atoms are in shells

The maximum number of electrons in each shell, going from the middle to the outside, is 2-8-8-18

1112

Sodium

Atomic number = Mass Number =

2 - 8 - 1

p+

n

2311

23 protons & neutrons

12 neutrons

In a neutral sodium atom the number of protons (11) = the number of electrons (11)

- 11 protons____________________

4 5

Beryllium

Atomic number = Mass Number =

2 - 2

p+

n

94

9 protons & neutrons

5 neutrons

In a neutral beryllium atom the number of protons (4) = the number of electrons (4)

- 4 protons____________________

1616

Sulfur

Atomic number = Mass Number =

2 - 8 - 6

p+

n

3216

32 protons & neutrons

16 neutrons

In a neutral sulfur atomthe number of protons (16) = the number of electrons (16)

- 16 protons____________________

7 7

Nitrogen

Atomic number = Mass Number =

2 - 5

p+

n

147

14 protons & neutrons

7 neutrons

In a neutral nitrogen atom the number of protons (7) = the number of electrons (7)

- 7 protons____________________

1414

Silicon

Atomic number = Mass Number =

2 - 8 - 4

p+

n

2814

28 protons & neutrons

14 neutrons

In a neutral silicon atom the number of protons (14)= the number of electrons (14)

- 14 protons____________________

1920

Potassium

Atomic number = Mass Number =

2 - 8 - 8- 1

p+

n

3919

39 protons & neutrons

20 neutrons

In a neutral potassium atom the number of protons (19) = the number of electrons (19)

- 19 protons____________________