Review of Atomic Theory

What is matter? Mather is anything that has mass and volume. What isn’t matter?

What isn’t matter? Energy is not matter as it has no mass or volume. Eg. Light, heat, electricity Forces: gravity, magnetism All matter is composed of elements.

What is an element? An element is any substance that cannot be broken down into simpler substances by ordinary chemical means. Elements are made up of atoms.

What is an atom? An atom is the smallest unit of an element that still retains the properties of an element. Eg. Oxygen, Carbon, Gold, Silver, Mercury

What is a compound? a pure substance made up of two or more types of atoms chemically joined in fixed proportions Eg: water, sugar, salt H2O, NaCl

Do you remember the parts of the atom?

Parts of the atom

Bohr Model Indicates number of ELECTRONS in each of the ENERGY LEVEL / SHELL / ORBITAL. Each energy level can only hold so many electrons: 1st shell: 2 electrons 2nd shell: 8 electrons 3rd shell: 8 electrons 4th shell: 18 electrons

Difference between atomic mass and atomic number Atomic Number = protons Atomic Mass = protons = neutrons

Fun Facts you should know about atoms: Where each subatomic particle can be found. What charge each subatomic particle has. Why are atoms are neutral? Atoms are mostly empty space – what subatomic particle accounts for most of the volume? What subatomic particles account for most of an atom’s mass? How to determine the number of protons, neutrons, electrons

Each atoms prefers to have a FULL valence shell An atom will lose or gain electrons to achieve a Stable Octet (full valence shell). When a neutral atom gains electrons  negative When an atom loses electrons  positive

What is an ion? An ion is an atom that has gained a charge Can be positive (cation) or negative (anion)

Where can an atom get another electron? From an atom wanting to get rid of one of course:

Naming Binary Ionic Compounds First name unchanged, Second name add -ide NaCl MgCl2 MgO LiF

Naming Ionic Compounds with Polyatomic Ions CaCO3 is calcium carbonate Na0H MgSO4 KNO3

Two types of Compounds Ionic Covalent

What are isotopes? Isotopes are different forms of the same element (same number of protons) but with different number of neutrons. Atomic number same (protons) Atomic mass different (p + n)

Isotopes are identified by their Atomic Mass Lithium 6 lithium 7 lithium 8

You try: Write the atomic number and mass of each carbon isotope You try: Write the atomic number and mass of each carbon isotope. Normal Carbon has 6 protons.

You try: Write the atomic number and mass of each carbon isotope You try: Write the atomic number and mass of each carbon isotope. Normal Carbon has 6 protons. Mass 12 13 14 Protons 6 6 6 Neutrons 6 7 8

Why are isotopes important?

Why are isotopes important? Isotopes are unstable and will decay at a reliable rate over long periods of time Scientists compare original (parent) isotope to resulting (daughter) isotope to determine age of very old geological features. Eg. Carbon dating.

Homework Read pages 29-33 of your text and answer Questions #1, 2, 5, 6, 7 on page 33.