Unit 2

• 1. Elements are composed of atoms
• 2. Atoms of an element are identical/same properties
• 3.Atoms of different elements combine and form compounds
• 4. Atoms are not created, destroyed, or broken down by a chemical reation

Matter is not created or destroyed in a normal chemical reaction

a pure compound always contains definate or constant proportions of the elements by mass

If two elements form more than one compound then the ratio between the masses of the second element will be small whole numbers

• Nucleus-protons(+) and neutrons(no charge)
• Electrons (-)

The total number or protons and neutrons in a nucleus. protons never change, neutrons can change

the number of protons in an atom/element. (periodic table)

Atoms of the same elements that have different number of neutrons in the nucleus

• listed on the periodic table is an average of all the isotopes of that element.
• mass* abundace=amu (add both amu for isotopes together)

vertical colums containing elements with similar properties

horizontal rows in the periodic table

use chemical symbols and subscripts to express the number of atoms of each element in a compound

• compounds formed of discrete, electrically neutral molecules which are formed by sharing electrons
• 2 non-metals

compounds formed of large groups of electically charged particles called ions which are formed by tranferrint electrons from one atom to another

O₂,  N_2,  F_2,  Cl_2,  Br_2,  I_2,  H₂

• compunds whose crystals contain water molecules in fixed ratios
• ionic compund * # water

several atoms covalently bound that travel as a set

lowest whole number ratio of ions in an ionic lattice

• Binary ionic compoud-two elements (metal and non)
• Ternary ionic compount- three elements (metal and polyatomic ion)

Binary molecular compound-contains two elements (two nonmetals)

When a compound dissolves in water to give ions

• Binary acid- aqueous solution with two elements (hydrogen and nonmetal)
• Ternary oxo acid-aqueous solution twith three elements (hydrogen, nonmetal, and oxygen)

• Cations-positve
• Anions-negative
• monotomic
• polyatomic

• One charge write the name of the parent metal follwed by the word "ion" (group 1,2, and Al in group three)
• Multiple charge(transition) write the name of the parent metal followed by charge in roman numerals, then the word "ion"
• Zinc & Silver no roman numeral

Write the name of the nonmetal, drop the ending, add -ide, and the word "ion"

Oxo-anions are names using the root name and the suffixes -ate or -ite.

-ate corresponds to one more oxygen than ite

if 1 or 2 hydrogen's is in front of the ono-anions we add Hydrogen or dihydrogen to the anion name

The charge is reduced by 1 for each H added.

• form more poly atomic ions, so we add hypo- and per-
• per- and one oxygen to -ate
• hypo- minus one oxygen to -ite
• bromate, iodate, flurate

• two non-metals
• greek prefixes
• 1-mono, 2-di, 3-tri, 4-tetra, 5-penta, 6-hexa, 7-hepta, 8-octa, 9-nona, 10-deca

-ide, change to ic and hydro- in front and acid

Hydro         ic acid

• -ate ions make ic acids
• -ite ions make ous acid

• Describes what happens when a chemical reaction occurs
• reation -> products

contain the same number of each type of atom on both sides of the equation