WGU D425 INTRO TO CHEMISTRY
OBJECTIVE ASSESSMENT ACTUAL EXAM
2026-2027 QUESTIONS WITH VERIFIED
ANSWERS 100% CORRECT PASS
GUARANTEED
1. Which statement best describes an element?
A. A physical combination of two or more substances
B. A substance that can be separated by physical methods
C. A pure substance consisting of one type of atom
D. A substance made only from two or more compounds
CORRECT ANSWER: C. A pure substance consisting of one type of atom
Rationale:
An element contains only one type of atom and cannot be chemically broken down into a
simpler substance.
2. Which is an example of a homogeneous mixture?
A. Granite
B. Saltwater
C. Sand and water
D. Oil and water
, CORRECT ANSWER: B. Saltwater
Rationale:
A homogeneous mixture has a uniform composition throughout. Salt dissolved completely in
water forms a homogeneous solution.
3. How many significant figures are in 0.00520?
A. 2
B. 3
C. 4
D. 5
CORRECT ANSWER: B. 3
Rationale:
Leading zeros are not significant. The digits 5, 2, and the trailing zero are significant.
4. A substance has a mass of 45.0 g and a volume of 15.0 mL. What is its density?
A. 0.333 g/mL
B. 3.00 g/mL
C. 30.0 g/mL
D. 60.0 g/mL
, CORRECT ANSWER: B. 3.00 g/mL
Rationale:
$$ Density=\frac{mass}{volume} $$ $$ Density=\frac{45.0\,g}{15.0\,mL}=3.00\,g/mL $$
5. An atom has 17 protons and 18 neutrons. What is its mass number?
A. 17
B. 18
C. 35
D. 36
CORRECT ANSWER: C. 35
Rationale:
$$ Mass\ number = protons + neutrons $$ $$ 17+18=35 $$
The element is chlorine because it has 17 protons.
6. An electrically neutral atom has 12 protons. How many electrons does it have?
A. 6
B. 10
C. 12
D. 24
, CORRECT ANSWER: C. 12
Rationale:
A neutral atom has equal numbers of protons and electrons. Therefore, 12 protons means 12
electrons.
7. What happens when an atom loses an electron?
A. It becomes a negatively charged ion
B. It becomes a positively charged ion
C. Its atomic number decreases
D. It becomes a neutron
CORRECT ANSWER: B. It becomes a positively charged ion
Rationale:
Electrons have negative charge. Losing an electron leaves more positive charge than negative
charge, producing a cation.
8. Which element is most electronegative?
A. Sodium
B. Carbon
C. Oxygen
D. Fluorine
OBJECTIVE ASSESSMENT ACTUAL EXAM
2026-2027 QUESTIONS WITH VERIFIED
ANSWERS 100% CORRECT PASS
GUARANTEED
1. Which statement best describes an element?
A. A physical combination of two or more substances
B. A substance that can be separated by physical methods
C. A pure substance consisting of one type of atom
D. A substance made only from two or more compounds
CORRECT ANSWER: C. A pure substance consisting of one type of atom
Rationale:
An element contains only one type of atom and cannot be chemically broken down into a
simpler substance.
2. Which is an example of a homogeneous mixture?
A. Granite
B. Saltwater
C. Sand and water
D. Oil and water
, CORRECT ANSWER: B. Saltwater
Rationale:
A homogeneous mixture has a uniform composition throughout. Salt dissolved completely in
water forms a homogeneous solution.
3. How many significant figures are in 0.00520?
A. 2
B. 3
C. 4
D. 5
CORRECT ANSWER: B. 3
Rationale:
Leading zeros are not significant. The digits 5, 2, and the trailing zero are significant.
4. A substance has a mass of 45.0 g and a volume of 15.0 mL. What is its density?
A. 0.333 g/mL
B. 3.00 g/mL
C. 30.0 g/mL
D. 60.0 g/mL
, CORRECT ANSWER: B. 3.00 g/mL
Rationale:
$$ Density=\frac{mass}{volume} $$ $$ Density=\frac{45.0\,g}{15.0\,mL}=3.00\,g/mL $$
5. An atom has 17 protons and 18 neutrons. What is its mass number?
A. 17
B. 18
C. 35
D. 36
CORRECT ANSWER: C. 35
Rationale:
$$ Mass\ number = protons + neutrons $$ $$ 17+18=35 $$
The element is chlorine because it has 17 protons.
6. An electrically neutral atom has 12 protons. How many electrons does it have?
A. 6
B. 10
C. 12
D. 24
, CORRECT ANSWER: C. 12
Rationale:
A neutral atom has equal numbers of protons and electrons. Therefore, 12 protons means 12
electrons.
7. What happens when an atom loses an electron?
A. It becomes a negatively charged ion
B. It becomes a positively charged ion
C. Its atomic number decreases
D. It becomes a neutron
CORRECT ANSWER: B. It becomes a positively charged ion
Rationale:
Electrons have negative charge. Losing an electron leaves more positive charge than negative
charge, producing a cation.
8. Which element is most electronegative?
A. Sodium
B. Carbon
C. Oxygen
D. Fluorine
