Structure of the Atomor “Let’s Get up and Atom”

Chemical Symbols

Nucleus/ clouds

Subatomic Particles

Atomic Terms

Chemical Symbols

Capitals matter! Element symbols contain ONE capital letter

followed by lowercase letter(s) if necessary.

Co vs. COMetal that

forms bright blue solid

compounds.

Poisonous gas.

Subatomic Particles

POSIT IVECHARG E

PROT ONS

NEUT RALCHARG E

NEUT RONS

NUCLEUS

NEG AT IVE CHARG E

ELECT RONS

AT OM

Most of the atom’s mass. Atomic Numberequals the # of...

in a neutral atom

NUCLEUS ELECTRONS

PROTONS NEUTRONS NEGATIVE CHARGE

POSITIVE CHARGE

NEUTRAL CHARGE

ATOM

Subatomic Particles

Quarks

• 6 types

• 3 quarks = 1 proton or 1 neutron

He

II. Electron Clouds (shells) Contain electrons (-)

Orbital

Energy Levels

Bohr Model Diagrams

Orbital

Region where there is 90% probability of finding an electron.

Can’t pinpoint the location of an electron.

Density of dots represents degree of probability.

Orbitals have different shapes.

Energy Levels

Electrons can only exist at certain energy levels.

Low energy levels are close to the nucleus.

Each energy level (n) can hold 2n2 electrons.

Bohr Model Diagrams

Simplified energy levels using Bohr’s idea of circular orbits.

e-

e-

Maximum e-

Level 1 2e-

Level 2 8e-

Level 3 18e-

Level 4 32e-

Lithium Atomic #: 3 Mass: 7

# of p: 3 # of e: 3 # of n: 4

p

pn

nn n

p

e-

Can replace with:

3p4n

Bohr Model Activity

Choose a number between 1 & 18. Find your element by the atomic number you picked. Draw a Bohr Model diagram for your element on your marker board.

• Round off the mass listed on the table and subtract the atomic # to find the # of neutrons.• Abbreviate the # of ‘p’ and ‘n’ in the nucleus.

Have a partner check your drawing. Repeat with a new element.

Atomic terms

Atomic Number (Z)

Mass Number (A)

Atomic Mass unit (amu)

Isotopes

Atomic Number (Z): Number of Protons

In a neutral atom the # of protons = number of electrons

P+ = e- 14+ = 14-

Mass Number

Total # of nucleons (protons + neutrons) in nucleus of atom.

# of P+ (+) # of n-

Always a whole number.

# of neutrons = A - Z

# of neutrons = mass # - atomic #

© Addison-Wesley Publishing Company, Inc.

Atomic Mass

atomic mass unit (amu) = unit to describe the mass of an atom

1 u u = 1/12 the mass of a 12C atom

1 proton = 1 u1 u 1 neutron = 1 u1 u

1 u u = 1.67 10-24 g

© Addison-Wesley Publishing Company, Inc.

ParticleParticle SymbolSymbol ChargeCharge Mass in amuMass in amu Mass in grams

Electron e" -1 1/1 840 amu 9.11 x 109.11 x 10-28-28gg

Proton P+ +1 1 amu 1.67 x 101.67 x 10-24-24gg

Neutron N+- or n0 0 1 amu 1.67 x 10 1.67 x 10 -24-24gg

We’ve only just begun…….