1.
A neutron carries a positive charge.
Correct Answer
B. False
Explanation
A neutron is a subatomic particle that carries no electrical charge, making it neutral. It is found in the nucleus of an atom alongside protons, which carry a positive charge. Electrons, which orbit the nucleus, have a negative charge. The neutrality of neutrons plays a crucial role in stabilizing the atomic nucleus.
2.
How many atoms of nitrogen are in the formula NH4OH?
Correct Answer
D. 1
Explanation
The formula NH₄OH, or ammonium hydroxide, contains one nitrogen atom. This is because NH₄OH consists of the ammonium ion (NH₄⁺) and hydroxide ion (OH⁻), with the nitrogen atom located in the NH₄⁺ part of the compound. Therefore, there is only one nitrogen atom in NH₄OH.
3.
How many atoms of oxygen are in Sn(SO4)2?
Correct Answer
D. 8
Explanation
In the chemical formula Sn(SO₄)₂, there are two sulfate ions (SO₄). Each sulfate ion contains 4 oxygen atoms, so multiplying 4 oxygen atoms by 2 gives a total of 8 oxygen atoms in the compound. Therefore, the formula contains 8 oxygen atoms.
4.
Identify the atomic number of the element of Xenon.
Correct Answer
D. 54
Explanation
Xenon (Xe) is a chemical element with the atomic number 54. The atomic number of an element refers to the number of protons in the nucleus of one atom of that element. Xenon, being a noble gas, is located in Group 18 of the periodic table. Its atomic number of 54 means that each Xenon atom contains 54 protons. This also dictates its position in the periodic table and its chemical properties, which include being colorless, odorless, and inert under most conditions due to its full electron shell.
5.
Which of the following determines the atomic number of an atom?
Correct Answer
C. Number of protons
Explanation
The atomic number of an atom is determined by the number of protons in its nucleus. Protons are positively charged particles that define the element itself. For example, all carbon atoms have 6 protons, so the atomic number of carbon is 6. The number of protons determines the identity of the element and its position on the periodic table.
6.
A proton has a charge that is equal in force but opposite in charge of each electron.
Correct Answer
A. True
Explanation
The statement is true because a proton has a positive charge, while an electron has a negative charge. The magnitude of their charges is equal, but they have opposite signs. This means that the force between a proton and an electron is attractive, as opposite charges attract each other. Therefore, the statement is correct.
7.
Protons and electrons are about equal in mass.
Correct Answer
B. False
Explanation
Protons and electrons are not about equal in mass. Protons have a mass of approximately 1 atomic mass unit (AMU), while electrons have a mass that is about 1/1836th of an AMU. Therefore, protons are much heavier than electrons.
8.
The mass of an atom depends on the number of protons and neutrons in its nucleus.
Correct Answer
A. True
Explanation
The mass of an atom is determined by the number of protons and neutrons in its nucleus. Protons and neutrons have a relatively large mass compared to electrons, so they contribute significantly to the overall mass of the atom. Electrons, on the other hand, have a negligible mass. Therefore, the more protons and neutrons an atom has, the greater its mass will be. This statement is true as it accurately describes the relationship between the mass of an atom and the number of protons and neutrons in its nucleus.
9.
How do you determine the mass number of an atom?
Correct Answer
C. It is equal to the number of protons plus the number of neutrons.
Explanation
The mass number of an atom is determined by adding the number of protons and the number of neutrons. This is because protons and neutrons both contribute to the mass of an atom, while electrons have negligible mass compared to protons and neutrons. Therefore, the correct answer is that the mass number is equal to the number of protons plus the number of neutrons.
10.
Atoms of the same element with different numbers of neutrons are called__________.
Correct Answer
A. Isotopes
Explanation
Atoms of the same element with different numbers of neutrons are called isotopes. Isotopes have the same number of protons and electrons, which determine the element, but they differ in the number of neutrons. This difference in neutrons leads to variations in the atomic mass of the isotopes. Isotopes can have different physical and chemical properties due to their varying atomic masses, but they still belong to the same element.
11.
In the name carbon-14, the 14 is the _________________.
Correct Answer
A. Mass number
Explanation
The correct answer is mass number. The mass number refers to the total number of protons and neutrons in the nucleus of an atom. In the name carbon-14, the 14 represents the mass number, indicating that the carbon atom has 6 protons and 8 neutrons.
12.
What is the atomic number of the element Xenon?
Correct Answer
B. 54
Explanation
Xenon is a noble gas, and its atomic number is 54. The atomic number of an element represents the number of protons in its nucleus, and for Xenon, this number is 54. Xenon is located in Group 18 of the periodic table and is used in a variety of applications, including lighting and medical imaging.
13.
The atomic number of an atom is determined by the number of
Correct Answer
C. Protons
Explanation
The atomic number of an atom is defined by the number of protons in its nucleus. This number is unique to each element and determines its identity on the periodic table. Electrons and neutrons, though crucial to the atom's properties, do not determine the atomic number.
14.
An atom that has a different number of electrons and protons is called a(n)
Correct Answer
A. Ion
Explanation
An ion is an atom that has gained or lost one or more electrons, resulting in an imbalance between the number of protons (positive charge) and electrons (negative charge). If an atom gains electrons, it becomes negatively charged (anion), and if it loses electrons, it becomes positively charged (cation). This difference in charge defines an ion.
15.
Neutrons have a ____________ charge.
Correct Answer
C. Neutral
Explanation
Neutrons are subatomic particles found in the nucleus of an atom. They have no charge, meaning they are electrically neutral. Neutrons, along with protons, contribute to the mass of an atom but do not affect its charge. The presence of neutrons in an atom can also lead to the formation of isotopes.
16.
How many protons are in tin-100?
Correct Answer
B. 50
Explanation
Tin (Sn) has an atomic number of 50, which means that every atom of tin, including the isotope tin-100, contains 50 protons in its nucleus. The number 100 refers to the mass number, which is the sum of protons and neutrons. In this case, tin-100 has 50 neutrons, which, combined with the 50 protons, gives a mass number of 100.
17.
How many neutrons are in tin-100?
Correct Answer
B. 50
Explanation
Tin-100 has a mass number of 100, which represents the total number of protons and neutrons in the nucleus. Since tin has 50 protons (as indicated by its atomic number), the number of neutrons in tin-100 is also 50 (100 mass number - 50 protons = 50 neutrons).
18.
Is tin-100 a common isotope?
Correct Answer
B. No
Explanation
Tin-100 is not a common isotope of tin. While tin has several stable isotopes (such as tin-112, tin-114, tin-116, and others), tin-100 is a radioactive isotope that is not found in significant quantities in nature. It is studied more in the context of nuclear physics and has a relatively short half-life.
19.
What is the charge on an atom with 10 protons and 8 electrons?
Correct Answer
A. 2
Explanation
The charge of an atom is determined by the difference between the number of protons (positive charge) and electrons (negative charge). In this case, the atom has 10 protons and 8 electrons, resulting in a net positive charge of +2. This happens because the atom has 2 more protons than electrons, so it is a positively charged ion (cation).
20.
Which of the following describes the process in which an atom gains or loses electrons?
Correct Answer
A. Ionization
Explanation
Ionization refers to the process where an atom gains or loses one or more electrons, resulting in the formation of an ion. If an atom loses electrons, it becomes positively charged (cation), and if it gains electrons, it becomes negatively charged (anion). This process is fundamental to many chemical reactions and the behavior of elements in different states.