Chemistry Unit 3 Bonding

Cation

positively charged ion that if formed by the loss of electrons

Anion

negatively charged ion that is formed by gaining electrons

Polyatomic Ion

a group of 2 or more atoms covalently bonded together, that acts as a single charged unit in a chemical reaction

Ionic Bond

formed by the loss and gain of electrons (cation and anion)

Properties of ionic compounds

really high melting points, conduct electricity when dissolved in water (soluble)

Bond

the force of attraction that holds atoms or ions together, allowing them to act as a unit

Covalent Bond

two atoms held together by sharing a pair of electrons are joined by a covalent bond

Properties of Molecular (covalent) Compounds

low melting points, poor conductors of electricity, don’t dissolve (in water)(not soluble)

Acids

an acid is a compound that contains one or more ionizable (ability to give off) Hydrogen atoms

acids are covalent compounds

mole

a unit of measurement of representative particles equal to 6.022 × 10^ 23

used as a counting unit to measure atoms

a word that represents a number

Avogadro’s number

a mole = 6.022 × 10^ 23 which is Avogadro’s number

Representative Particle

the smallest particle of a substance

Representative particle of an element is a…

atom

Representative particle of a compound is a…

molecule

Diatomic's

elements that cannot exist alone in nature 

Br 2 I 2 N 2 Cl 2 H 2 O 2 F 2

“Particle” can mean —— or ——-

atom or molecule

Atomic Mass

atomic mass for an element can be found on the periodic table

expressed in units of amu and g/mole

Molar mass

For molecules you must calculate the sum (add up) of all the atomic masses (of each element) that make up the particle 

unit is g/mole 

Percent compositions

percent compositions tells you by mass what percent of each elements is present in a compound

Mole conversions

Elements: grams → moles → atoms

Compounds: grams → moles → molecules → atoms