The Electrical Nature Of Matter i543g

The Electrical Nature of Matter Or Where do the charges come from?

Atoms are electrically neutral. • In an atom, the number of protons, is equal to the number of electrons. • For example: Oxygen has 8 protons and 8 electrons; that means +8 + -8 = 0 • What happens if . . .

. . .that oxygen atom gains electrons? • Oxygen has 8 protons and 8 electrons when an atom. • For each electron you add, it adds more negative charge. Lets use the same equation: – +8 + -9 (add an electron) = -1 – +8 + -10 (add 2 electrons) = -2

• When the total charge is not zero, they are called IONs.

Loosing electrons makes you: • POSITIVE!! • Since you are getting rid of (having fewer) negative charges, your overall charge is positive.

Why is it that it is the electrons that are lost or gained? • Think about the picture of an atom you drew in middle school . . . . • In the center or nucleus are the protons and neutrons. These are not changed by ordinary actions. • But, what happens if you slide your feet across a carpet, when you have socks on? • You just picked up loose electrons .

Losing and Gaining Electrons • Electrons on the outer edges (Valence Electrons) are not being pulled very tightly by the protons in the nucleus • Also atoms have certain configurations of outer electrons that they prefer – THEY ALL WANT TO HAVE 8 ELECTRONS!! • Atoms will loose or gain electrons to achieve these configurations forming IONS

Valence Electrons- s & p only Group 1 = 1 Valence eGroup 2 = 2 Valence eGroup 13 = 3 Valence eGroup 14 = 4 Valence e-

Group 15 = 5 Valence eGroup 16 = 6 Valence e-

Group 17 = 7 Valence eGroup 18 = 8 Valence e-

Atoms will lose or gain electrons to get 8 VALENCE e- ( not 8 total, 8 outer e-)

Metals Like to Lose • Elements in group 1A, 2A, and 3A like to lose electrons (a.k.a. groups 1, 2, & 13) • Losing electrons = POSITIVE CHARGE (+) +1 • Group 1 elements tend to have a ____ charge. +2 • Group 2 elements tend to have a ____ charge. +3 • Group 13 elements tend to have a ____ charge.

Non-Metals Like to Gain • Elements in group 15, 16, and 17 like to gain electrons • Gaining electrons = NEGATIVE CHARGE (-) -3 • Group 15 elements tend to have a ____ charge. -2 • Group 16 elements tend to have a ____ charge. -1 • Group 17 elements tend to have a ____ charge.

What about 4A and 8A?? • Elements in group 14 can go either way. They can either lose or gain 4 electrons, so they prefer to share . . . • Lose electrons = + 4 Gain electrons = - 4 • Group 18) have a very stable configuration and do not lose or gain electrons unless a great deal of energy is added. Therefore they do not form IONS.

Mass Number • The sum of the number of protons and neutrons in the nucleus of an atom of a particular element. • the number in the square is an average of all of the isotopes of that element. • Isotopes have different numbers of neutrons, but the same number of protons

For each element below, give #protons, #neutrons and preferred ionic charge: 1. 2. 3. 4. 5. 6. 7. 8. 9.

Sodium Aluminum Magnesium Fluorine Oxygen Potassium Calcium Silicon Arsenic

10. Bromine 11. Carbon 12. Sulfur 13. Boron 14. Lithium 15. Chlorine 16. Argon 17. Hydrogen 18. Germanium