chemistry atomic structures, BH & Lewis diagrams, ionic compounds, polyatomic atoms, molecular atoms, acids and bases, pH

what is chemistry?

the study of matter

what is matter?

anything that has both mass and volume

what is mass?

amount of matter that makes an object

what is volume?

amount of space occupied

what is an element?

• pure substances that cannot be broken down by chemical means

• made up of only 1 type of atom

• ex: magnesium, iron, sodium

what is a compound?

• pure substances that has 2 of more different elements in a fixed ratio chemically bonded together

• ex: carbon dioxide, water

atomic structure

proton, neutron, electron

• atoms are electrically neutral

what does the atomic number tell us about the atomic structure?

tells how many protons and neutrons an atom has

what does the atomic mass tell us about the atomic structure?

average mass of an element’s atom. mass of protons & neutrons

how do you find an element’s neutrons by looking at the element in a periodic table?

mass # - atomic # = # of neutrons

properties of metals

• found on the left side of the periodic table (except hydrogen)

• solids at room temp.

• lustrous, conductive, malleable

non-metals

• found on the right side + hydrogen

• all states (solid, liquid, gas)

• dull, brittle, non-conductive

transition metals

• middle of the table

• change from metallic to non-metal properties

metalloids

• zigzag (staircase on the right side)

• some metallic & some nonmetallic properties

groups/families

• vertical columns (up down)

• group # = # of valence electrons

periods

• horizontal rows (left right)

• # of periods = # of orbits (shells)

valence electrons

electrons on the outermost shell of the atom

what does the lewis structure tell us about atoms?

only shows valence electrons and the chemical symbol

what does the bohr rutherford diagram tell us about atoms?

• # of protons

• # of neutrons

• # of electrons

subscripts

Tiny numbers below an element’s symbol

Tells how many of that atom we have in one particle

Coefficient

number placed in-front of a chemical formula/symbol

tells us how many of that particle we have

Parenthesis

Groups elements together

Atom

Basic building block of all matter

Molecule

Formed when 2 or more atoms join together

ions

Positively or negatively charged atom

Cation

Positive ions

Usually formed by metals who lose electrons

Anion

Negatively charged ion

Usually formed by non-metals that gain electrons

Bohr rutherford diagram for ion

Lewis structure for ion

Ionic compounds

Formed between metals & non metals

Neutral

Solids at room temp, brittle, good insulators

Naming ionic compounds

Metal name remains same

Nonmetal ending changes to -ide

Multivalent

Found in the middle of the periodic table

Able to form more than 1 type of ion

The charge will be written after the name of the metal as a roman numeral written in brackets

Polyatomic ions

Ion formed by more than one (poly-) atom

One unit, cannot make any changes to their subscripts

Most are anions

Molecular compounds

Non-metal atoms joining together by sharing electrons

Covalent bonding

Sharing of electrons, each atom not strong enough to take each other’s atoms

Diatomic elements

Elements that will always come in pairs

Usually exist as a gas

HOFBrINCl

Hydrogen, oxygen, fluorine, bromine, iodine, nitrogen, chlorine

Nomenclature molecular compounds

Only used in molecular compounds

Chemical reaction

One or more substances change into different substances

Word equation

Names of chemicals written out in full

Irreversible reaction occurs

Reactants written on the left

Products written on the right

Chemical equation

Chemical symbols & formulas are used to represent the chemicals

Dont forget HOFBrINCl

Skeleton equation

Unbalanced chemical equation

Reactant

Chemical used during the reaction

Product

Chemical that is produced during chemical reaction

Law of conservation of mass

In any given chemical reaction, the total the reactants equals the total mass of the product

Acids

Substances that produce hydrogen ions (H+) when dissolved in water

Acid properties

• sour

• Conductive

• React w metals

• React w carbonates & bicarbonates

• Neutralize bases

• pH lower than 7

Bases

Substance that produces hydroxide ions (OH¯) when dissolved in water

Bases properties

Bitter

Conductive

Dont react w metals

Feels slippery

Neutralize acids

pH level higher than 7

Neutral

pH of 7

Neutral substance is distilled water

Neither acidic nor basic

Neutralization

Type of reaction in which acid and a base react to form an ionic compound

acid + base → water + ionic compound

pH

Quantitative measure of how acidic or basic a solution is

Stands for power of hydrogen

pH scale

logarithmic, for every change in 1 pH concentration changes by 10x

• ph 2 to 1 substance has 10x higher H+ concentration

• ph 7 to 9 substance has 100x lower H+ concentration