WGU D425 Intro to Chem | PA | Questions and Answers |
2025 Update | 100% Correct
Atomic Structure & The Periodic Table
1. What are the three fundamental particles of an atom?
A) Proton, neutron, isotope
B) Proton, electron, ion
C) Proton, neutron, electron
D) Cation, anion, electron
2. What does the atomic number of an element represent?
A) The number of protons and neutrons
B) The number of protons
C) The number of neutrons
D) The mass of the atom
3. Isotopes of an element have the same number of ____ but different numbers of ____.
A) neutrons, protons
B) electrons, protons
C) protons, neutrons
D) protons, electrons
4. In the periodic table, elements are arranged in order of:
A) Atomic mass
B) Atomic number
C) Number of neutrons
D) Density
5. Which group on the periodic table contains the noble gases?
A) Group 1
B) Group 2
C) Group 17
D) Group 18
6. Elements in the same group (vertical column) have similar chemical properties
because they have the same:
A) Atomic mass
B) Number of electron shells
, C) Number of valence electrons
D) Number of neutrons
7. An atom that has gained or lost electrons is called a(n):
A) Isotope
B) Ion
C) Molecule
D) Element
8. A cation is an atom that has:
A) Gained electrons, giving it a negative charge
B) Lost electrons, giving it a positive charge
C) Gained protons, giving it a positive charge
D) Lost neutrons, becoming neutral
9. The mass number of an atom is defined as:
A) The number of protons
B) The number of electrons
C) The number of protons plus the number of neutrons
D) The atomic weight
10. Which subatomic particle is responsible for the chemical behavior of an element?
A) Proton
B) Neutron
C) Electron
D) Nucleus
Chemical Bonding & Nomenclature
11. A covalent bond is formed when atoms:
A) Transfer electrons from one to another
B) Share one or more pairs of electrons
C) Have a large difference in electronegativity
D) Are both metals
12. An ionic bond is typically formed between:
A) Two metal atoms
B) Two nonmetal atoms
C) A metal and a nonmetal
D) Two noble gases
, 13. What is the correct name for the compound CaCl₂?
A) Calcium chlorine
B) Calcium(I) chloride
C) Calcium chloride
D) Monocalcium dichloride
14. What is the formula for sodium carbonate?
A) NaCO₃
B) Na₂CO₃
C) NaC
D) S₂CO₃
15. The correct name for the compound N₂O₅ is:
A) Nitrogen oxide
B) Dinitrogen pentoxide
C) Nitrogen pentoxide
D) Nitrous oxide
16. In a polar covalent bond, the electrons are:
A) Shared equally
B) Transferred completely
C) Shared unequally
D) Not involved in bonding
17. What is the oxidation state (charge) of oxygen in most of its compounds?
A) +1
B) -1
C) +2
D) -2
18. The correct formula for iron(III) oxide is:
A) FeO
B) Fe₂O₃
C) Fe₃O₂
D) I₃O₂
19. Which of the following is a polyatomic ion?
A) Na⁺
B) O²⁻
2025 Update | 100% Correct
Atomic Structure & The Periodic Table
1. What are the three fundamental particles of an atom?
A) Proton, neutron, isotope
B) Proton, electron, ion
C) Proton, neutron, electron
D) Cation, anion, electron
2. What does the atomic number of an element represent?
A) The number of protons and neutrons
B) The number of protons
C) The number of neutrons
D) The mass of the atom
3. Isotopes of an element have the same number of ____ but different numbers of ____.
A) neutrons, protons
B) electrons, protons
C) protons, neutrons
D) protons, electrons
4. In the periodic table, elements are arranged in order of:
A) Atomic mass
B) Atomic number
C) Number of neutrons
D) Density
5. Which group on the periodic table contains the noble gases?
A) Group 1
B) Group 2
C) Group 17
D) Group 18
6. Elements in the same group (vertical column) have similar chemical properties
because they have the same:
A) Atomic mass
B) Number of electron shells
, C) Number of valence electrons
D) Number of neutrons
7. An atom that has gained or lost electrons is called a(n):
A) Isotope
B) Ion
C) Molecule
D) Element
8. A cation is an atom that has:
A) Gained electrons, giving it a negative charge
B) Lost electrons, giving it a positive charge
C) Gained protons, giving it a positive charge
D) Lost neutrons, becoming neutral
9. The mass number of an atom is defined as:
A) The number of protons
B) The number of electrons
C) The number of protons plus the number of neutrons
D) The atomic weight
10. Which subatomic particle is responsible for the chemical behavior of an element?
A) Proton
B) Neutron
C) Electron
D) Nucleus
Chemical Bonding & Nomenclature
11. A covalent bond is formed when atoms:
A) Transfer electrons from one to another
B) Share one or more pairs of electrons
C) Have a large difference in electronegativity
D) Are both metals
12. An ionic bond is typically formed between:
A) Two metal atoms
B) Two nonmetal atoms
C) A metal and a nonmetal
D) Two noble gases
, 13. What is the correct name for the compound CaCl₂?
A) Calcium chlorine
B) Calcium(I) chloride
C) Calcium chloride
D) Monocalcium dichloride
14. What is the formula for sodium carbonate?
A) NaCO₃
B) Na₂CO₃
C) NaC
D) S₂CO₃
15. The correct name for the compound N₂O₅ is:
A) Nitrogen oxide
B) Dinitrogen pentoxide
C) Nitrogen pentoxide
D) Nitrous oxide
16. In a polar covalent bond, the electrons are:
A) Shared equally
B) Transferred completely
C) Shared unequally
D) Not involved in bonding
17. What is the oxidation state (charge) of oxygen in most of its compounds?
A) +1
B) -1
C) +2
D) -2
18. The correct formula for iron(III) oxide is:
A) FeO
B) Fe₂O₃
C) Fe₃O₂
D) I₃O₂
19. Which of the following is a polyatomic ion?
A) Na⁺
B) O²⁻
