Chem exam 1 (chp 1-4)

Atom

The smallest identifiable unit of an element

Law of Conservation of Mass

Matter and mass is never created or destroyed in a chemical reaction

Parts of the atom

Nucleus, the mass of the atom made of protons and neutrons, and the electron cloud, large space around nucleus where electrons are.

Proton mass

1 amu

Neutron mass

1 amu

electron mass

0 amu

Charge of proton

+1

Charge of Neutrons

0

Charge of Electrons

-1

Atomic Mass Unit

unit we use to talk about mass of subatomic particles, amu

Ion, sometimes called a charged Ion

an atom with unequal number of protons and electrons

Cations

A positive ion with more protons than electrons

Anions

A negative ion with more electrons than protons

Atomic mass

weighted average of all the isotopes of an element

Isotope

An atom of an element that has a different number of neutrons and therefore a different mass number

Mass number definition

The mass of a singular isotope

Mass number formula

number of neutrons + number of protons

To find which isotope is most abundant

Atomic mass-mass number of isotope. Which has a smaller difference.

1A

Alkali metals

2 A

Alkaline earth metals

7A

halogens

8A

Noble gases

Alkali metals have a charge of

+

Alkaline metals have a charge of

2+

Halogens have a charge of

-

Noble gases have a charge of

nothing, they are neutral

Nonmetals try to become stable by….

Have the same number of electrons as the closest noble gas

in isotopic notation BLANK is on the top

mass number

in isotopic notation BLANK is on the bottom

atomic number/number of protons

Matter

anything that occupies space and has mass

Atoms

submicroscopic particles that are the building blocks of matter

Molecules

two or more atoms joined to one another in specific pattern

Three states of matter

solid, liquid, gas

Solids

Close together atoms that may vibrate or oscillate but do not move around together, creating a fixed volume and rigid structure.

Types of solids

Crystalline or amorphous

Crystalline

atoms form in geometric with long-range repeating order

Liquid

Atoms are close together but are able to move around and by each other, creating a fixed volume.

Gas

Atoms have a great distance and are able to move around freely, thereby making this matter compressible

Chemistry

The science that tries to understand matter by studying how atoms and molecules behave

Mass

Measure of the quantity of matter

Physical property

Properties we can observe without changing the chemical composition

Chemical property

Properties we can observe only when we change the chemical composition

Qualitative Property

Qualities we can observe

Quantitative Property

Quantities we can observe

Physical change

Affects the form of a chemical substance but not the composition

Chemical change

Process in which one or more substances are converted to one or more new substances, occurs when bonds between atoms are broken or formed

Pure Substance

Has the same composition throughout and cannot be separated through physical means

Elements

Smallest unite of substances that cannot be broken down further

Compounds

Substance made up of 2 or more elements combined in definite proportions and cannot be separated by physical means

Mixtures

2 or more pure substances combined in variable proportions that can be separated by physical means

Diatomic molecules

Certain elements that only exist as two identical atoms bonded together

Chemical formula

A way to describe the exact chemical composition of a compound by giving chemical symbols and proportions

Homogeneous mixture

Mixture with a uniform composition

Heterogeneous mixture

Mixture that does not have a uniform composition

Exothermic

Energy change that releases energy into the environment

Endothermic

Energy change that absorbs energy from the environment

Aluminum

Al

Argon

Ar

Arsenic

As

Barium

Ba

Beryllium

Be

Boron

B

Bromine

Br

Cadmium

Cd

Calcium

Ca

Carbon

C

Cesium

Cs

Chlorine

Cl

Chromium

Cr

Cobalt

Co

Copper

Cu

Fluorine

F

Francium

Fr

Gallium

Ga

Germanium

Ge

Gold

Au

Helium

He

Hydrogen

H

Iodine

I

Iron

Fe

Krypton

Kr

Lead

Pb

Lithium

Li

Magnesium

Mg

Manganese

Mn

Mercury

Hg

Neon

Ne

Nickel

Ni

Nitrogen

N

Oxygen

O

Phosphorus

P

Platinum

Pt

Potassium

K

Radon

Rn

Rubidium

Rb

Scandium

Sc

Selenium

Se

Silicon

Si

Silver

Ag

Sodium

Na