Chapter 2

Question 1

AMU

Answer 1

relative atomic masses are expressed in atomic mass units

Question 2

period

Answer 2

horizontal row of the periodic table

Question 3

group

Answer 3

vertical row of the periodic table

Question 4

nucleus

Answer 4

tiny core of the atom, composed of protons and neutrons and containing all of the positive charge and most of the mass of the atom

Question 5

atomic number

Answer 5

The number of protons in the nucleus of the atom (Z)

Question 6

proton

Answer 6

The unit of positive charge in the nucleus of an atom

Question 7

neutron

Answer 7

a nuclear particle with a mass of about 1 u and no electric charge

Question 8

x-rays

Answer 8

radiation similar to visible light but with much higher energy and much more penetration

Question 9

noble gases

Answer 9

non-chemically reactive, colorless gases composed of single atoms

Question 10

halogens

Answer 10

diatomic molecules that readily form negatively charged components of salts.

Question 11

alkali metals

Answer 11

are soft metals that do not exist in nature as free elements due to their reactivity; readily form positively charged components of salts.

Question 12

alkaline earth metals

Answer 12

harder, less reactive, elements than alkali metals; however, they react vigorously with oxygen.

Question 13

transition metals

Answer 13

occupy the central block of the periodic table; except those in column 12, characteristically have incompletely filled d-subshell of electrons
– can form colored compounds
– commonly possess different oxidation states
– many can be magnetic
– have high densities, melting and boiling points
– most found in 3rd period, as well as Mo in 4th period, have biological significance (as activating components of enzymes)