Struktur Atom Practice Questions
UN (Indonesia) · UN Kimia · 136 free MCQs with instant results and detailed explanations.
136
Total
38
Easy
67
Medium
31
Hard
Start Practicing Struktur Atom
Take a timed quiz or customize your practice session
Sample Questions from Struktur Atom
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What is the atomic number of an element?
A.
The number of protons in the nucleus
B.
The total number of neutrons and protons
C.
The average mass of an element's isotopes
D.
The number of electrons in a neutral atom
Show Answer & Explanation
Correct Answer: A
The atomic number is defined as the number of protons in the nucleus of an atom, which determines the element's identity.
Q2
Easy
Which subatomic particle has a negative charge?
A.
Proton
B.
Neutron
C.
Electron
D.
Nucleus
Show Answer & Explanation
Correct Answer: C
Electrons are the subatomic particles that carry a negative charge, while protons carry a positive charge and neutrons have no charge.
Q3
Easy
If an atom has 12 protons, how many electrons does it have in a neutral state?
A.
6
B.
12
C.
18
D.
24
Show Answer & Explanation
Correct Answer: B
In a neutral atom, the number of electrons equals the number of protons. Therefore, if there are 12 protons, there are also 12 electrons.
Q4
Medium
Which scientist proposed the planetary model of the atom, suggesting electrons orbit the nucleus?
A.
Niels Bohr
B.
Erwin Schrödinger
C.
J.J. Thomson
D.
John Dalton
Show Answer & Explanation
Correct Answer: A
Niels Bohr proposed the planetary model of the atom, which describes electrons moving in fixed orbits around the nucleus, similar to planets around the sun.
Q5
Medium
If an atom has an atomic number of 15 and mass number of 31, how many neutrons does it contain?
A.
15
B.
16
C.
31
D.
46
Show Answer & Explanation
Correct Answer: B
To find the number of neutrons, subtract the atomic number from the mass number: Neutrons = Mass number - Atomic number = 31 - 15 = 16.
Q6
Medium
Which of the following statements about isotopes is correct?
A.
Isotopes have different atomic numbers.
B.
Isotopes have the same number of neutrons.
C.
Isotopes have different mass numbers.
D.
Isotopes are chemically identical to one another.
Show Answer & Explanation
Correct Answer: C
Isotopes are atoms of the same element with different mass numbers due to varying numbers of neutrons, while they have the same atomic number.
Q7
Medium
Which of the following statements about isotopes is correct?
A.
Isotopes have the same number of protons but different numbers of neutrons.
B.
Isotopes have different numbers of protons and electrons.
C.
Isotopes have the same chemical properties as different elements.
D.
Isotopes differ in their atomic number.
Show Answer & Explanation
Correct Answer: A
Isotopes are defined as atoms of the same element that have the same number of protons but different numbers of neutrons, which results in different mass numbers.
Q8
Hard
Which of the following quantum numbers is not allowed for an electron in an atom?
A.
n = 2, l = 1, m_l = -1
B.
n = 3, l = 2, m_l = 3
C.
n = 4, l = 0, m_l = 0
D.
n = 1, l = 0, m_l = 0
Show Answer & Explanation
Correct Answer: B
The magnetic quantum number (m_l) must be an integer between -l and +l, inclusive. For l = 2, m_l can be -2, -1, 0, 1, or 2. However, m_l = 3 is not allowed, making option B incorrect.
Q9
Hard
An atom has the following electron configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵. What is the atomic number of this atom?
A.
35
B.
36
C.
34
D.
33
Show Answer & Explanation
Correct Answer: A
The atomic number is determined by counting the total number of electrons in the configuration. Here, 2 + 2 + 6 + 2 + 6 + 2 + 10 + 5 = 35. Thus, the atomic number is 35.
Q10
Hard
Which of the following statements accurately describes the role of neutrons in the atomic nucleus?
A.
Neutrons determine the chemical properties of an atom.
B.
Neutrons provide stability to the nucleus by offsetting repulsive forces between protons.
C.
Neutrons carry a positive charge that attracts electrons.
D.
Neutrons increase the atomic number of an element.
Show Answer & Explanation
Correct Answer: B
Neutrons are neutral particles that help stabilize the nucleus by reducing the electrostatic repulsion between positively charged protons.
Showing 10 of 136 questions. Start a quiz to practice all questions with scoring and timer.
Practice All 136 Questions →Other UN (Indonesia) Subjects
Struktur Atom — UN (Indonesia) UN Kimia Practice Questions Online
This page contains 136 practice MCQs for the chapter Struktur Atom in UN (Indonesia) UN Kimia. The questions are organized by difficulty — 38 easy, 67 medium, 31 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.