Chemistry: Semester 1 Final Exam Study Guide

Law of Conservation of Mass
mass is neither created nor destroyed

Law of Definite Proportions
chemical compounds contain the same elements in the same proportions by mass regardless of the size or source of the compound

Electron
negatively charged particles surrounding the nucleus of an atom

neutron
neutral particles in the nucleus of an atom

proton
positively charged particle in nucleus of an atom

nuclear forces
short range proton-proton, proton-neutron, and neutron-neutron forces that hold the nucleus of an atom together

element
a pure substance that cannot be broken down into simpler, stable substances and is made of one type of atom

compound
substance that can be broken down into simple, stable substances. Each compound is made from the atoms of two or more elements that are chemically bonded

physical property
characteristic that can be observed or measured without changing the identity of the substance

physical change
change in a substance that does not involve a change in the identity of the substance

chemical property
relates to a substance’s ability to undergo changes that transform in into different substances

chemical change
change in which one or more substances are converted into different substances

products
substances formed by a chemical change

reactants
substances that react in a chemical change

mixture
blend of two or more kinds of matter, each retaining its own identity and properties

group
vertical columns on the periodic table; also called families

period
horizontal rows of elements on the periodic table

noble gases
elements in Group 18, unreactive gases at room temperature

atomic number
number of protons in each atom of that element

mass number
total number of protons and neutrons that make up the nucleus of an isotope

average atomic mass
weighted average of the atomic masses of naturally occurring isotopes of an element

quantum
the minimum amount of energy that can be gained or lost by an atom

density
A measure of how much mass is contained in a given volume

5 parts of Dalton’s Atomic Theory
1. all matter is composed of atoms
2. atoms of a given element are identical in size, mass, and other properties
3. atoms cannot be subdivided, created, or destroyed
4. atoms of different elements combine in simple whole-number ratios to form chemical compounds
5. in chemical reactions, atoms are combined, separated, or destroyed

ground state
lowest energy state of a quantized system

excited state
state in which an atom has more energy than it does at ground state

isotope
atoms of the same element that have different masses; different number of neutrons

mass number of carbon?
mass number of carbon?
what is 12.0107?

atomic number of carbon?
atomic number of carbon?
what is 6?

element name of C?
element name of C?
what is Carbon?

element symbol of Carbon?
element symbol of Carbon?
what is C?

number of protons in an element
same as atomic number

mass number – atomic number
number of neutrons