1.
Particles of matter that make up the nucleus of the atom are ___.
Correct Answer
A. Protons and neutrons
Explanation
The correct answer is protons and neutrons. Protons and neutrons are the particles that make up the nucleus of an atom. Protons have a positive charge, while neutrons have no charge. Electrons, on the other hand, are found outside the nucleus and have a negative charge. Ions and isotopes are not particles of matter that make up the nucleus of an atom.
2.
All of the mass of the atom is in the ___.
Correct Answer
A. Nucleus
Explanation
The correct answer is nucleus. The nucleus is the central part of an atom that contains almost all of its mass. It is made up of protons and neutrons, which are the subatomic particles that contribute to the mass of the atom. Electrons, on the other hand, are much smaller in mass and are found in the electron cloud surrounding the nucleus. Therefore, the majority of the mass of an atom is concentrated in its nucleus.
3.
Horizontal rows of the periodic table are called ___.
Correct Answer
A. Periods
Explanation
Horizontal rows of the periodic table are called periods. Each period represents a different energy level or shell in an atom. The elements within a period have the same number of electron shells.
4.
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 but different numbers of neutrons, which results in a difference in their atomic mass. This variation in the number of neutrons does not affect the element's chemical properties but can impact its stability and radioactive behavior. Isotopes are commonly used in various fields, such as medicine, archaeology, and environmental studies, for tracing, dating, and analyzing different processes.
5.
Elements that are gases, are brittle, and are poor conductors at room temperature are ___.
Correct Answer
A. Non-metals
Explanation
Non-metals are the elements that are gases, brittle, and poor conductors at room temperature. Non-metals have properties opposite to metals, as they do not have the ability to conduct heat and electricity efficiently, and tend to be brittle rather than malleable. Examples of non-metals include oxygen, nitrogen, and carbon.
6.
A certain atom has 38 protons, 38 electrons, and 50 neutrons. Its mass number is ___.
Correct Answer
A. 88
Explanation
The mass number of an atom is the sum of its protons and neutrons. In this case, the atom has 38 protons and 50 neutrons, so the sum is 38 + 50 = 88. Therefore, the correct answer is 88.
7.
Why are the noble gases stable?
Correct Answer
A. They have a full outer shell of electrons
Explanation
The noble gases are stable because they have a full outer shell of electrons. This means that their outermost energy level is completely filled with electrons, which makes them less likely to react with other elements and form chemical bonds. As a result, noble gases tend to exist as individual atoms rather than forming compounds. This stability is due to the fact that having a full outer shell satisfies the octet rule, which states that atoms tend to gain, lose, or share electrons in order to achieve a full outer shell.
8.
An atom that has gained 2 electrons and is now positively charged is specifically called a(n) ___.
Correct Answer
A. Cation
Explanation
When an atom gains electrons, it becomes negatively charged. However, in this question, it states that the atom has gained 2 electrons and is now positively charged. This indicates that the atom has actually lost 2 electrons, resulting in a positive charge. In chemistry, an atom that has lost electrons and has a positive charge is called a cation. Therefore, the correct answer is cation.
9.
Elements that fall along the "staircase" on the periodic table and have properties like metals and non-metals are called___.
Correct Answer
A. Metalloids
Explanation
Metalloids are elements that fall along the "staircase" on the periodic table. They have properties that are intermediate between metals and non-metals. They exhibit characteristics of both metals and non-metals, such as being able to conduct electricity like metals but being brittle like non-metals. Therefore, metalloids are the correct answer to this question.
10.
What period and group (in that order) is barium found in?
Correct Answer
D. 6, 2
Explanation
Barium is found in period 6 and group 2 of the periodic table. The period number indicates the energy level of the outermost electrons, and the group number represents the number of valence electrons. Barium, with an atomic number of 56, has its outermost electrons in the 6th energy level and 2 valence electrons, placing it in period 6 and group 2.
11.
Given the following information, Iodine - 128, how many electrons are present?
Correct Answer
A. 53
Explanation
The atomic number of iodine is 53, which represents the number of protons in the nucleus of an iodine atom. Since atoms are electrically neutral, the number of electrons in an atom is also equal to the atomic number. Therefore, there are 53 electrons present in an iodine atom.
12.
An atom that has gained two additional electrons would have a charge of ___.
Correct Answer
B. -2
Explanation
When an atom gains two additional electrons, it becomes negatively charged because electrons have a negative charge. The negative charge is indicated by the minus sign. Therefore, the correct answer is -2, indicating that the atom has gained two electrons and has a charge of -2.
13.
Argon is considered a noble gas and non-reactive. What makes argon such a stable atom?
Correct Answer
A. 8 electrons in outer shell
Explanation
The stability of an atom is determined by the arrangement of its electrons. In the case of argon, it has 8 electrons in its outer shell, which is a full shell. This full outer shell gives argon a stable electron configuration, making it non-reactive and therefore considered a noble gas. The presence of a full outer shell means that argon does not need to gain or lose electrons to achieve stability, which is why it is such a stable atom.
14.
An atom found in period 4, group 7 would be considered a non-metal.
Correct Answer
B. False
Explanation
An atom found in period 4, group 7 would not be considered a non-metal. In the periodic table, group 7 is known as the halogens, which are non-metals. Therefore, an atom in this group would be a non-metal.
15.
In an atom, the atomic number is useful because a physical science student can determine the number of protons and electrons.
Correct Answer
A. True
Explanation
The atomic number of an atom represents the number of protons in its nucleus. Since an atom is electrically neutral, it also has the same number of electrons as protons. Therefore, by knowing the atomic number, a physical science student can determine both the number of protons and electrons in an atom. Hence, the statement is true.
16.
If Tellurium - 127 were to lose 4 neutrons, the new mass would be 122.
Correct Answer
B. False
Explanation
This statement is false because losing 4 neutrons would result in a decrease in the atomic mass of Tellurium - 127, not a decrease to mass 122. The new mass would be 123, not 122.
17.
Oxygen has 5 valence electrons.
Correct Answer
B. False
Explanation
Oxygen actually has 6 valence electrons. Valence electrons are the electrons in the outermost energy level of an atom, and for oxygen, the electron configuration is 1s2 2s2 2p4. The 2s and 2p orbitals in the second energy level are considered the valence orbitals, and there are a total of 6 electrons in these orbitals for oxygen. Therefore, the correct answer is False.
18.
Sodium has 11 electrons total, but only 2 electrons in its first energy level.
Correct Answer
A. True
Explanation
Sodium has 11 electrons in total, and according to the electron configuration, the first energy level can hold a maximum of 2 electrons. Therefore, it is true that sodium has only 2 electrons in its first energy level.
19.
The elements on the modern Periodic Table are arranged by decreasing atomic number.
Correct Answer
B. False
Explanation
The elements on the modern Periodic Table are arranged by increasing atomic number. This means that as you move from left to right across a period or from top to bottom down a group, the atomic number of the elements increases. The atomic number represents the number of protons in an atom's nucleus, and it determines the element's identity. Therefore, the statement that the elements are arranged by decreasing atomic number is incorrect.
20.
Electrons farthest from the nucleus have a higher level of energy as compared to other electrons in the atom.
Correct Answer
A. True
Explanation
The statement is true because electrons that are farther from the nucleus have a higher energy level. This is due to the fact that the energy levels of electrons in an atom are quantized, meaning they can only exist at specific energy levels. The energy levels closer to the nucleus are lower, while the energy levels farther away are higher. Electrons in higher energy levels have more potential energy and are therefore farther from the nucleus.
21.
Nuclear fusion occurs naturally in the sun.
Correct Answer
A. True
Explanation
Nuclear fusion is the process by which two or more atomic nuclei come together to form a heavier nucleus, releasing a large amount of energy in the process. This process is the main source of energy in stars, including our sun. Therefore, it is true that nuclear fusion occurs naturally in the sun.
22.
The three subatomic particles are ___.
Correct Answer
A. Protons, neutrons, and electrons
Explanation
The three subatomic particles are protons, neutrons, and electrons. Protons are positively charged particles found in the nucleus of an atom, while neutrons are neutral particles also found in the nucleus. Electrons are negatively charged particles that orbit around the nucleus. These three particles together make up the structure of an atom.
23.
The mass of an electron is so small, we sometimes say it's mass is negligible.
Correct Answer
A. True
Explanation
The statement is true because the mass of an electron is indeed very small compared to other particles. The mass of an electron is approximately 9.1 x 10^-31 kilograms, which is about 1/1836th the mass of a proton. This small mass allows electrons to move easily and participate in various chemical reactions and electrical currents. Therefore, it is common to refer to the mass of an electron as negligible in many contexts.
24.
Two isotopes of hydrogen are hydrogen-2 and hydrogen-3. These isotopes differ from one another by one proton.
Correct Answer
B. False
Explanation
The statement is false because the isotopes of hydrogen, hydrogen-2 and hydrogen-3, differ from one another by one neutron, not one proton. Isotopes have the same number of protons but different numbers of neutrons.
25.
The region around the nucleus occupied by the electrons is called the negative zone.
Correct Answer
B. False
Explanation
The region around the nucleus occupied by the electrons is actually called the electron cloud or electron shell. This is because the electrons are not confined to a specific path or orbit, but rather exist in a probability cloud around the nucleus. Therefore, the correct answer is False.