Question

Answer

Explanation

1 The atomic number of an atom is always equal to the number of its

(1) protons, only
(2) neutrons, only
(3) protons plus neutrons
(4) protons plus electrons

1

Atomic #= # protons

2 Which subatomic particle has no charge?

(1) alpha particle      (3) neutron
(2) beta particle       (4) electron

3

Alpha +

Beta –

Neutron no charge

Electron -

3 When the electrons of an excited atom return to a lower energy state, the energy emitted can result in the production of

(1) alpha particles      (3) protons
(2) isotopes              (4) spectra

4

Definition of spectra

4 The atomic mass of an element is calculated using the

(1) atomic number and the ratios of its naturally occurring isotopes
(2) atomic number and the half-lives of each of its isotopes
(3) masses and the ratios of its naturally occurring isotopes
(4) masses and the half-lives of each of its isotopes

3

definition

5 The region that is the most probable location of an electron in an atom is

(1) the nucleus      (3) the excited state
(2) an orbital         (4) an ion

2

Electron outside the atom in orbitals

6 Which is a property of most nonmetallic solids?

(1) high thermal conductivity
(2) high electrical conductivity
(3) brittleness
(4) malleability

3

Nonmetals

Low melting point poor conductors of heat/electricity

brittle

7 Alpha particles are emitted during the radioactive decay of

(1) carbon-14      (3) calcium-37
(2) neon-19         (4) radon-222

4

Table N decay mode

8 Which is an empirical formula?

(1) P₂ O₅        (3) C₂ H₄
(2) P₄ O₆       (4) C₃ H₆

1

Lowest ration of elements

9 Which substance can be decomposed by a chemical change?

(1) Co      (3) Cr
(2) CO     (4) Cu

2

Which is not an element?

10 The percent by mass of calcium in the compound calcium sulfate
(CaSO₄ ) is approximately

(1) 15%      (3) 34%
(2) 29%      (4) 47%
 

2

(40/40+32+4(16) ) x100%