AP Chemistry Note Packet 2: Atoms, Molecules & Ions

the law of definite proportions

a given compound always contains exactly the same proportions of elements by mass

the law of multiple proportions

when two elements combine to form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers

Avagadro’s Hypothesis

at the same temperature and pressure, equal volumes of different gases contain the same number of particles

What are the four points of Dalton’s Atomic Theory of Matter?

1. All matter is made of atoms (has been modified)

2. All the atoms of a given element are identical (has been modified)

3. Compounds are formed by the combination of different atoms in the ratio of small whole numbers

4. A chemical reaction only involves the combination, separation, or rearrangement of atoms; atoms are neither created nor destroyed in the course of ordinary chemical reactions

What was JJ Thomson’s model called?

Plum Pudding model

What are the three types of radioactive emissions?

alpha, beta gamma

What is an alpha emission?

a helium nucleus

What is a beta emission?

an electron

What is a gamma emission?

pure energy

What did Rutherford do?

Shoot helium particles at a thin sheet of gold, showed that the plum pudding model couldn’t be true

What is a hydrogen atom with 1 neutron called?

deuterium

What is a hydrogen atom with 2 neutrons called?

tritium

Are electrons shared or lost/gained in covalent bonds?

shared

What types of elements form covalent bonds?

nonmetals

Anything molecular indicates what type of bond?

covalent

cations

positive ions, often metals since metals lose electrons

anions

negative ions, often nonmetals since nonmetals gain electrons

polyatomic ions

units of atoms behaving as one entity

ionic solids

electrostatic (coulombic) forces hold ions together