Atoms and Structure Unit Test Knowt

study

Atom

the smallest unit of matter.

How do you calculate the average atomic mass?

[(Mass 1)(% 1)]+ [(mass2)(% 2)]

Relationship between Dalton’s Atomic Theory and the Law Conservation of Mass

the law conservation of mass is part of the atomic theory     

Steps of Dalton’s Atomic Theory

1. All matter is composed of atoms.

2. Atoms of the same element are identical; atoms of different elements are not.

3. Atoms cannot be subdivided, created, or destroyed.

4. Atoms combine in simple whole-number ratios to form compounds.

5. Atoms are combined, separated, or rearranged in chemical reactions.

If you change the number of protons, what do you get?

a different atom

If you change the number of neutrons, what do you get?

an isotope

Dalton's Atomic Theory

early model describing how atoms behave.

Law of Conservation of Mass

matter cannot be created or destroyed.

Electron

negatively charged particle found in the electron cloud; 1/837 AMU

An atom contains 14 protons

Silicon

Two atomic particles are always equal in a neutral atom?

protons and electrons

Proton

positively charged particle found in the nucleus; 1 AMU

Neutron

neutral particle found in the nucleus; 1 AMU

Nucleus

dense center of the atom containing protons and neutrons.

Electron Cloud

region around the nucleus where electrons are found.

Atomic Number

number of protons in an atom.

Atomic Mass

total number of protons and neutrons.

Chemical Symbol

one or two letter abbreviation for an element.

Isotope

atoms of the same element with different numbers of neutrons.

Average Atomic Mass

weighted average of all isotopes.

Mole

unit for counting particles (6.02 × 10²³ particles).

Hyphen Notation

way to write isotopes for example Carbon 14.

Neutral Atom

atom with equal protons and electrons.

Plum Pudding Model

Thomson's model showing electrons in a positive pudding.

Nuclear Model

Rutherford's model with a dense nucleus and orbiting electrons.

Billiard Ball Model

Dalton's solid sphere model of the atom.

Cathode Ray Tube

Thomson's experiment that discovered electrons.

Gold Foil Experiment

Rutherford's experiment that discovered the nucleus.

AMU or Atomic Mass Unit

unit used to measure atomic mass.

Molecular Mass or Molar Mass

total mass of a compound in grams per mole.