Unit 1: Atoms and Molecules (1)

Lessons 1, 2, 3 - Possibly the first half

How do we classify matter?

Composition at the molecular level

Examples: multiple types of atoms or molecules?

Draw a matter flow chart

Matter —> pure substances & mixtures

pure substances —> elements & compounds

mixtures —> mechanical mixture, solution

Pure substance vs Mixture

Pure substance

• Every particle is identical

• Classified as solid, liquid, or gas

• Has predictable properties

  • i.e. melting point, conductivity, lustre

Mixture

• Has multiple types of molecules

• Not classified as solid, liquid, or gas

• Properties very with composition

Element vs. Compound

Element

• Every atom is identical

• Ex. Au

Compound

• Every molecule is identical but there are multiple types of atoms

• Ex. H2O

Solution vs. Mechanical Mixture

Solution

• Homogenous mixture because they are UNIFORM

Mechanical mixture

• Heterogeneous mixture because they have visibly distinct parts

Atom vs. Molecule vs. Ion

• Atom: The smallest unit of an element, consisting of protons, neutrons, and electrons.

• Molecule: A group of two or more atoms bonded together

• Ion: An atom or molecule that has gained or lost one or more electrons, resulting in a net electrical charge.

Chart relating position, charge, and relative mass of the proton, neutron, and electron

Particle	Position	Charge	Relative Mass (to Proton)
Proton	Nucleus	+1	1
Neutron	Nucleus	0	slightly more than a proton
Electron	Outside nucleus	-1	basically 0

How do you calculate the:

1. Atomic number

2. Atomic mass

3. Charge

1. # of protons

2. # of protons + # of neutrons

3. # of protons - # of electrons

How do you calculate:

1. Number of protons

2. Number of neutrons

3. Number of electrons

1. Atomic mass - neutrons = protons; Atomic number == # ofprotons

2. Atomic mass - protons or atomic number = neutron

3. Proton - charge = electrons

State the model of Daltons atom + drawing

• Atom is the smallest particle

• Different elements have different atoms

State the model of Thomson atom + drawing

• Discovered electrons

• Atom is a ball of positive charge with negative electrons embedded in it

State the model of Rutherford atom + drawing

• Discovered the nucleus

• Protons and neutrons make up the nucleus, surrounded by a cloud of electrons

State the model of Bohr atom + drawing

• Electrons are limited to specific energy levels and orbits

Tips and tricks for finding electrons based off of periodic table placement?

Columns: # of valence electrons

Rows: # of valence shells

What is an orbital?

A region of space where an electron is very likely to be found

2 Rules of electrons when filling orbitals

1. Always go to the lowest available energy level

2. Two electrons can go in each orbital

List the orbitals in order of energy level stopping at 3p

1s, 2s, 2p, 3s, 3p