Chapter 2 - Atoms, Ions, and the Periodic Table

Question 1

Law of Conservation of Mass

Answer 1

Mass is not gained or lost in a chemical reaction

Question 2

Law of Definite Proportions

Answer 2

A compound always has the same mass ratio of the elements that compose it

Question 3

Dalton’s Atomic Theory

Answer 3

All matter is composed of small, indivisible particles, called atoms. All atoms of a given element are identical both in physical and chemical properties. Atoms are not created or destroyed in chemical reactions. Atoms combine in simple, fixed, whole-number rations to form molecules. In a chemical reaction, atoms rearrange into new combinations, obeying the Law of Conservation of Mass.

Question 5

Structure of an atom

Answer 5

They are divisible. They are composed of subatomic particles, but they don’t have the same properties as the host.

Question 6

Nucleus

Answer 6

Dense center of the atom

Question 7

Protons

Answer 7

Positively charged subatomic particles

Question 8

Neutrons

Answer 8

Uncharged subatomic particles

Question 9

Electrons

Answer 9

Negatively charged subatomic particles

Question 10

1 electron charge

Answer 10

1.592 x 10 ^-19 Coulomb

Question 11

Who did the Milliken Oil Drop experiment?

Question 12

The Gold Foil Experiment

Answer 12

By British physicist Ernest Rutherford in 1911. 1) Radioactive sample emits beam of alpha particles 2) Beam of alpha particles strikes gold foil 3) Flashes of light produced when alpha particles strike zinc-sulfide screen show that most alpha particles are transmitted with little or no deflection 4) minor deflections of alpha particles are seen occasionally 5) Major deflections of alpha particles are seen very rarely

Question 13

Cathode Ray Tubes

Answer 13

British physicist J.J. Thomson in 1897.

Question 14

Millikan Oil Drop Experiment

Answer 14

In 1909 by American physicist Robert A. Millikan

Question 15

1 electron charge

Answer 15

1.592 x10^-19 Coulomb

Question 16

Atomic number

Answer 16

Number of protons in an atom

Question 17

Atom number, Z

Answer 17

Number of protons in the nucleus of an atom

Question 18

Mass number, A

Answer 18

Number of protons and neutrons in the nucleus of an element’s atom, A = Z +N

Question 19

Neutron number, N

Answer 19

Number of neutrons in the nucleus of an element’s atom

Question 20

Isotope

Answer 20

An atom that contains a specific number of neutrons

Question 21

Isotopic symbol

Answer 21

A notation that adds the mass number, A, and atomic number, Z, to the elemental symbol, X. A/Z(X)

Question 22

Cations

Answer 22

Positively charged ions. They have fewer electrons than in the neutral atom, they are named by adding “ion” to the elemental name”.

Question 23

Anions

Answer 23

Negatively charged ions. They have more electrons than in the neutral atom. They are named by adding “-ide ion” to the suffix of the elemental name.

Question 24

Atomic mass: AMU scale

Answer 24

1 amu = 1/12 mass of one C-12 atom = 1.6606 x 10^-24 g

Question 25

Relative atomic mass

Answer 25

The isotopic mass of individual isotopes of an element, taking into account the naturally occurring relative abundance of each isotope.

Question 26

Relative atomic mass equation

Answer 26

(Isotope Mass of Isotope 1) x (Relative Abundance of Isotope 1) + (Isotope Mass of Isotope 2) x (Relative Abundance of Isotope 2)

Question 27

Group or Family

Answer 27

Elements in the same column having similar properties, with a roman numeral or arabic number

Question 28

Period

Answer 28

Horizontal row of elements having properties that tend to vary in a regular fashion, designated by Arabic numbers

Question 29

Alkali metals

Answer 29

Group 1 (IA) metals (not hydrogen). They are considered reactive because they react readily with other elements and compounds. React with water to produce hydrogen gas

Question 30

Alkaline earth metals

Answer 30

Group 2 (IIA) metals. More reactive than the transition metals but less reactive than alkali metals

Question 31

Halogens

Answer 31

Group 17 (VIIA) nonmetals. Exist naturally as diatomic molecules (2 atoms)

Question 32

Noble gases

Answer 32

Group 18 (VIIIA) nonmetals. Also called inert gases, do not chemically react with other elements under normal conditions

Question 33

Main-group elements

Answer 33

Contain any element in the eight groups designated with the letter A. In the Arabic numbering, groups 1, 2, and 13-18

Question 34

Transition metals

Answer 34

Contain any element in the 10 groups designated with the letter B. Arabic numbering, groups 3-12

Question 35

Inner-transition metals

Answer 35

Contain the lanthanides and actinides listed separately at the bottom of the table

Question 36

Diatomic molecules

Answer 36

Occur in pairs when not combined with other atoms.

Question 37

7 elements that exist as diatomic molecules

Answer 37

N2, O2, F2, Cl2, Br2, I2, H2

Question 38

Metals tend to lose electrons

Answer 38

To become cations, to have the same number of electrons as the last noble gas

Question 39

Nonmetals tend to gain electrons

Answer 39

To become anions, to have the same number of electrons as the next noble gas