Protons + Neutrons = NucleusElectrons “orbit” at various distances from nucleus

Electron configuration [2,8,8]

• All material objects are made of atoms• An atom is mostly empty space• Nucleus contains protons (+) and neutrons (0)

strongly held together• Electrons (-) are weakly bound to the nucleus

and can be easily removed

Summary of Subatomic Particles

Proton Neutron Electron

In nucleus In nucleus Outside nucleus

Tightly bound Tightly bound Weakly bound

Positively charged No charge Negative charge

Massive Massive Massless (relatively)

Check yourself.

____ are the charged parts of an atom.a. Only electrons b. Only protonsc. Neutrons onlyd. Electrons and neutronse. Electrons and protonsf. Protons and neutrons

Charged vs. Uncharged ParticlesPositively charged Uncharged Negatively charged

More protons (+) than electrons (-)

Equal number of p and e- More e- than p

Charged objects have an unequal number of protons and electrons.

The SI unit for charge is the Coulomb, C1 electron = -1.6 x 10-19 C1 proton = +1.6 x 10-19 C

CalculateObject # of excess protons/electrons Quantity of charge (Q) in

Coulombs, C

A 1 x 106 excess electrons

B 1 x 106 excess protons

C 2 x 1010 excess electrons

D 3.5 x 108 excess protons

E 4.67 x 1010 excess electrons

CalculateObject # of excess protons/electrons Quantity of charge (Q) in

Coulombs, C

A 1 x 106 excess electrons -1.6 x 10-13 C

B 1 x 106 excess protons +1.6 x 10-13 C

C 2 x 1010 excess electrons -3.2 x 10-9 C

D 3.5 x 108 excess protons +5.6 x 10-11 C

E 4.67 x 1010 excess electrons -7.5 x 10-9 C

Identify the following particles as being charged or uncharged. If charged, indicate whether they are charged positively or negatively. (n = neutron, p = proton, e = electron)

The amount of charge carried by a lightning bolt is estimated at 10 Coulombs. What quantity of excess electrons is carried by the lightning bolt?

The amount of charge carried by a lightning bolt is estimated at 10 Coulombs. What quantity of excess electrons is carried by the lightning bolt?

Answer: 6.25 x 1019 electronsMultiply the charge in Coulombs (10 C) by the conversion factor: (1 electron) / (1.6 x 10-19 C). The units of C cancel; the answer is in electrons.

What happens when a charged object comes near a neutral object?

Van de Graaff Generator

• Conductors are materials that permit electrons to flow freely from atom to atom and molecule to molecule.

• insulators are materials that impede the free flow of electrons from atom to atom and molecule to molecule.

polarization is the process of separating opposite charges within an object