The AtomUnit 4 Chemistry

DO NOW11/16/15

Answer the following questionsWhat do you know about the atom (ex: what is it made of?)

How big is the atom?How would you represent an atom on paper? Draw an atom:

Video

https://youtu.be/yQP4UJhNn0I

The Atom

The atom is the smallest particle of an element that retains the chemical properties of that element.

Consist of smaller particles and their number and arrangement of these particles within the atom determine it’s chemical property

Consists of 2 regions

Atoms 2 regions1) Nucleus: very small, located near the center of an atom

2) Electrons: surrounds the nucleus1)Large region compared to nucleus Nucleus

Electronshells

Subatomic particles

3 subatomic particles1. Protons: positive charge

Within nucleus2. Neutrons: neutral charge

3. Electrons: negative charge

Atomic AnatomyThe gas of an atom

What they look like“Subatomic Particles”

# e- = # p+

(for neutral atoms)

Particle(symbol)

Mass Charge Location

ProtonP+

1 +1 nucleus

Neutronn0

1 0 nucleus

Electrone-

0 -1 Outside,orbiting the nucleus

Chemical Symbol

Atomic #

Symbol 1st Letter

2nd letter

Name

Average Atomic Mass

# of p+ + # n0

# n0 = mass –atomic # (round

mass)

8

OOxygen15.999

Practice finding # e-, p+ and n0

7

NNitrogen

14.01

11

NaSodium22.99

15

PPhosphoru

s10.97

So how do we draw the atoms?Ex: Li – Three protons (atomic number)

3

LiLithium6.941

P+

P+P+

Four neutron.(mass – atomic number

n0

n0n0n0

p+ p

+p+

Three electrons,in two electron shells

n0

n0

e-e-

p+

p+

e-e-e-

____p+

____n0

Positions of electrons

Shell # # of e-

1 2 Go in as a pair

2 8 1 in each of 4 places then pair up

3 8 (sort of - more to come)

1 in each of 4 places then pair up

4 8 (sort of – more to come)

1 in each of 4 places then pair up

DO NOW11/17/19

Draw a Bohr model of sodium

11

NaSodium22.990