Chapter 1: Atoms

Question 1

Matter

Answer 1

Anything that occupies space and has mass. It is composed of particles and the structure of those particles determines the properties of matter.

Question 2

States of Matter

Answer 2

A classification of a form of matter as a solid, liquid, or gas.

Question 3

Solid

Answer 3

Atoms or molecules are packed close to one another in fixed locations.

• definite volume
• rigid shape

Question 4

Liquid

Answer 4

Atoms or molecules pack about as closely as they do in solid mater but are free to move relative to each other.

• fixed volume
• no fixed shape

Question 5

Gas

Answer 5

Atoms or molecules have a lot of space between them and are free to move relative to one another.

• Lacks a definite shape and volume
• Conforms to the shape and volume of its container

Question 6

Composition of Matter

Answer 6

Refers to the types of particles that compose it.

- pure substances or mixtures (heterogeneous or homogeneous mixtures)

Question 7

Pure Substances

Answer 7

Are composed of only one type of atom or molecule. Can be an element or a compound.

Question 8

Element

Answer 8

A substance that cannot be chemically broken down into a less complex substance.

Question 9

Compound

Answer 9

A substance composed of two or more molecules in fixed, definite proportions.

Question 10

Mixtures

Answer 10

Substances composed of two or more different types of atoms or molecules that can be combined in variable proportions.

Question 11

Heterogeneous Mixture

Answer 11

The composition varies from one region to another.

Question 12

Homogeneous Mixture

Answer 12

The composition remains the same throughout it.

Question 13

Law

Answer 13

A brief statement or equation that summarizes past observations and predicts future ones.

Question 14

Law of Conservation of Mass

Answer 14

Matter is neither created nor destroyed in a chemical reaction.

Question 15

Theory

Answer 15

A proposed explanation for observations and laws.

• based on well established and tested hypotheses
• predicts behavior beyond the observations and laws on which it was based

Question 16

The Law of Definite Proportions (aka The Law of Constant Composition)

Answer 16

All samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements. This allows mass ratio to be found.

Question 17

Mass Ratio

Answer 17

To find divide the larger mass by the smaller one.

Question 18

The Law of Multiple Proportions

Answer 18

When two elements (A and B) form two different compounds, the masses of element B that combine with one gram of element A can be expressed as a ratio of small whole numbers.

Question 19

Mass Number (A)

Answer 19

The molecular weight on the periodic table rounded to the nearest whole number. Can be found by taking the sum of the number of protons and neutrons in an atom.

Question 20

Atomic Number (Z)

Answer 20

Number of protons in an element. The atomic number defines the element.

Question 21

Periodic Table

Answer 21

A table that arranges all known elements in order of increasing atomic number. Elements with similar properties generally fall into columns.

Question 22

Chemical Symbol

Answer 22

A one or two letter abbreviation for an element that is listed directly below its atomic number on the periodic table.

Question 23

Isotopes

Answer 23

One of two or more atoms of the same element with the same number of protons but different numbers of neutrons and therefore different masses.

Question 24

Natural Abundance

Answer 24

The relative percentage of a particular isotope in a naturally occurring sample with respect to other isotopes of the same element.

Question 25

Ion

Answer 25

An atom or molecule with a net charge caused by the loss or gain of electron. The charge of the ion is indicated in the upper right corner of the chemical symbol.

Question 26

Cation

Answer 26

A positively charged ion.

Li+

Question 27

Anion

Answer 27

A negatively charge ion. F-

Question 28

Atomic Mass

Answer 28

The average mass in amu of the atoms of a particular element based on the relative abundance of the various isotopes. It is numerically equivalent to the mass in grams of one mole of the element. It is listed directly below the element’s symbol on the periodic table.

Question 29

Mass Spectroscopy

Answer 29

An experimental method of determining the precise mass and relative abundance of isotopes in a given sample using an instrument called a mass spectrometer.