Chapter 2

Question 1

What is an atom?

Answer 1

The smallest identifiable unit of an element.

Question 2

Law of conservation of mass states…

Answer 2

…In a chemical reaction, matter is neither created nor destroyed.

Question 3

Law of definite proportions states…

Answer 3

…that all samples of a given compound, regardless of their source or how they were prepared have the same proportions of their constituent elements.

Question 4

Atomic theory

Answer 4

Is the theory that each element is composed of tiny indestructible particles called atoms, that all atoms of a given element have the same mass and other properties, and that atoms combine in simple, whole-numer ratios to form compounds.

Question 5

Atomic Number (Z)

Answer 5

Number of protons in the nucleus of an atom; it describes the element

Question 6

Mass Number (A)

Answer 6

The sum of protons and neutrons.

Question 7

Isotopes

Answer 7

Atoms of the same element with different number of neutrons.

Question 8

Radioacitivy

Answer 8

Is the spontaneous emission of energy by some atoms; there are three types: alpha, beta, and gamma

Question 9

Alpha particles

Answer 9

+2 charge and large mass

Question 10

Beta particles

Answer 10

-1 charge and small mass

Question 11

Gamma particles

Answer 11

No charge, no mass

Question 12

During chemical changes, atoms can…

Answer 12

…lose or gain electrons, becoming charged particles called ions.

Question 13

Ions can occur in nature

Answer 13

True. Lithium and Fluorine are some of the examples.

Question 14

Positively charged ions

Answer 14

Are called cations (Li+)

Question 15

Negatively charged ions

Answer 15

Are called anions (F-)

Question 16

Ions behavior similarly to their corresponding atoms

Answer 16

False.

Question 17

Elements with similar properties…

Answer 17

…fall in the same columns (or groups)

Question 18

Metal elements…

Answer 18

…Lay on the left side of the table, tend to be good conductors of electricity, have malleability, good ductility, are often shiny, and tend to lose electrons.

Question 19

Non-metal elements…

Answer 19

…Lay on the upper right side (and hydrogen). These have varied properties; some are solids, other liquids, other gases, but they are mainly poor conductors of heat and electricity, and they all tend to gain electrons.

Question 20

Metalloid elements…

Answer 20

…Lay on the diagonal line between non-metal and metal elements. Many of them are also classified as semiconductors.

Question 21

Periodic table can also de divided into…

Answer 21

…Main-group elements (1A, 2A, 3A-8A) and transition elements (3B-2B)

Question 22

8A elements

Answer 22

Noble gases

Question 23

1A elements

Answer 23

Alkali metals; lose one electron, form 1+ ions

Question 24

2A elements

Answer 24

Alkaline earth metals; tend to lose two electrons and form 2+ ions

Question 25

7A

Answer 25

Halogens

Question 26

Mass of an electron

Answer 26

9.10x10-29

Question 27

Charge of an electron

Answer 27

-1.60x10-19C

Question 28

1 amu

Answer 28

1.60x10 raised to -19

Question 29

Molecular formula…

Answer 29

…provides the type and number of atoms in a given molecule

Question 30

Empirical formula…

Answer 30

…gives the relative number of each type of atom in a compound. It is a starting point for a molecular formula

Question 31

When going from molecular to empirical…

Answer 31

…look for a common factor.

Question 32

Structural formula

Answer 32

Provides structure but nothing else; good for paper

Question 33

Perspective

Answer 33

Attempts to illustrate a three dimensional state on a two dimensional state. It uses a wedge to represent an atom in the front; straight lines represent what is on the plane, and dashes represent what is behind.

Question 34

Ball and stick

Answer 34

Shows a relative size of the molecules

Question 35

Space-filling

Answer 35

Fills up the space between the atoms

Question 36

Polyatomic atoms

Answer 36

They are joined together as a molecule, but with a net charge on the overall structure.

Question 37

Atomic molecules

Answer 37

Exist in nature with single atoms as their basic unit

Question 38

Molecular elements

Answer 38

Normally do not exist as single atoms, but within a combination of two or more atoms bonded together. Most of them exist as polyatomic molecules.

Question 39

Molecular compounds

Answer 39

Made out of two or more covalently bound nonmetals

Question 40

Ionic compounds

Answer 40

Ions attracted to each other due to electrostatic forces. When it’s formed, an electron is lost by an element and gained by other.

Question 41

In a ionic compound…

Answer 41

…electrons are transferred. Usually the result of combinations between metals and nonmetals.

Question 42

In a molecular compound…

Answer 42

Electrons are shared (which is called covalent bonding)

Question 43

Arrangement of ions in a compound…

Answer 43

Three dimensional lattice.

Question 44

Why do covalent bonds have a lower potential energy?

Answer 44

Because the shared electrons interact with both nuclei.