Atoms
Isotopes/Perc
Atomic
Ions/Charges
ent
Mass/Number of Molecules
Abundance
10
10
10
10
20
20
20
20
30
30
30
30
40
40
40
40
50
50
50
50
Question 1 - 10
 Define an atom.
Answer 1 – 10
 The basic unit of a chemical element
Question 1 - 20
 Where is most of the mass of an atom located?
Answer 1 – 20
 Nucleus
Question 1 - 30
 Using a cathode ray tube, JJ Thompson discovered what
subatomic particle?
Answer 1 – 30
 Electrons
Question 1 - 40
 An element contains atoms with the same number of what
subatomic particle?
Answer 1 – 40
 Protons
Question 1 - 50
 What is a molecule?
Answer 1 – 50
 Two or more atoms with a definite arrangement held
together by chemical bonds.
Question 2 - 10
 The atomic number of an atom is equal to what?
Answer 2 – 10
 Protons
Question 2 - 20
 Calculate the atomic mass of Oxygen with 10 neutrons.
Answer 2 – 20
 18
Question 2 - 30
 Element X has an atomic number of 15 and an atomic mass
of 37. How many neutrons does element X have?
Answer 2 – 30
 22
Question 2 - 40
 What is the unit used for measuring the mass of atoms.
Answer 2 – 40
 Atomic mass units (amu)
Question 2 - 50
 What is the atomic number of Calcium? If Calcium has 24
neutrons, what is its atomic mass?
Answer 2 – 50
 The atomic number is 20, and its mass is 44.
Question 3 - 10
 Define an ion.
Answer 3 – 10
 An atom with a net positive or negative charge.
Question 3 - 20
 What is the difference between anions and cations?
Answer 3 – 20
 Anions have a negative charge and cations have a positive
charge.
Question 3 - 30
 What two subatomic particles must be equal in order to
create a neutral atom?
Answer 3 – 30
 Protons and Electrons
Question 3 - 40
 How many electrons are in S-2?
Answer 3 – 40
 18 electrons
Question 3 - 50
 Which atom has more electrons? Mg+1 or O-2?
Answer 3 – 50
 Mg+1
Question 4 - 10
 Define isotope
Answer 4 – 10
 Atoms of the same element with different numbers of
neutrons resulting in different atomic masses.
Question 4 - 20
 How many neutrons are in a Carbon isotope with a mass of
20?
Answer 4 – 20
 8 neutrons
Question 4 - 30
 Calculate the average atomic mass of these two Nitrogen
isotopes: 95% 14N and 5% 15N.
Answer 4 – 30
 14.05 amu
Question 4 - 40
 Calculate the average atomic mass of these three isotopes
of Oxygen: 78% 16O, 8% 17O, 14% 18O.
Answer 4 – 40
 16.36 amu
Question 4 - 50
 There are three isotopes of Silicon: 84% 28Si, 10% 29Si, 6%
30Si. A:
How many neutrons does each isotope have? B:
What is the average atomic mass? (Silicon has an atomic
number of 14)
Answer 4 – 50
 A: 1) 14 2) 15 3) 16
 B: 28.22 amu