1.
Which of these is NOT one of the basic pieces of an atom?
Correct Answer
D. Plasma
Explanation
Plasma is not one of the basic pieces of an atom. The basic pieces of an atom are electrons, protons, and neutrons. Plasma is actually a state of matter, similar to a gas, where the electrons have been stripped away from the atoms. It consists of charged particles and is often found in high-temperature environments, such as stars or lightning. While plasma is related to atoms, it is not considered a fundamental component of an atom itself.
2.
Which is an electron arrangement of a Period 2 element?
Correct Answer
D. 2.3
Explanation
The electron arrangement of a Period 2 element refers to the distribution of electrons in the energy levels or shells. In this case, the correct answer is 2.3. This means that the element has 2 electrons in the first energy level and 3 electrons in the second energy level. This arrangement is consistent with the electron configuration of elements such as lithium (Li) or beryllium (Be), which both belong to Period 2 of the periodic table.
3.
Which is the electron arrangement of an Alkali Metal?
Correct Answer
C. 2.8.1
Explanation
The electron arrangement of an Alkali Metal is 2.8.1. This means that in the outermost energy level, there is 1 electron. The first energy level can hold a maximum of 2 electrons, the second energy level can hold a maximum of 8 electrons, and the third energy level can hold a maximum of 8 electrons. Therefore, the electron arrangement of an Alkali Metal follows the pattern of 2 electrons in the first energy level, 8 electrons in the second energy level, and 1 electron in the third energy level.
4.
Which is an electron arrangement of a Halogen?
Correct Answer
B. 2.8.7
Explanation
The electron arrangement of a halogen is 2.8.7. This means that a halogen atom has 2 electrons in its first energy level, 8 electrons in its second energy level, and 7 electrons in its outermost energy level. This arrangement is characteristic of halogens, which are highly reactive nonmetals that have a tendency to gain one electron to achieve a stable electron configuration.
5.
Which description corresponds to a neutron?
Correct Answer
A. Mass = 1, electric charge = 0
Explanation
A neutron is a subatomic particle with a mass of 1 and no electric charge. It is found in the nucleus of an atom along with protons. The other options listed in the question do not correspond to the characteristics of a neutron.
6.
Which one of the following alkali metals is the most reactive?
Correct Answer
D. Cesium
Explanation
Cesium is the most reactive alkali metal because it has the largest atomic radius among the given options. As the atomic radius increases down the group, the outermost electron is further away from the nucleus, resulting in weaker attraction between the electron and the nucleus. This makes it easier for the outermost electron of cesium to be lost, leading to a higher reactivity.
7.
Astatine is a halogen found at the bottom of group 7 elements. Astatine is
Correct Answer
C. Least reactive halogen
Explanation
Astatine is the least reactive halogen because it is located at the bottom of group 7 elements. As you move down the halogen group, the reactivity decreases. Fluorine is the most reactive halogen, and as you move down the group, the reactivity decreases gradually. Astatine being at the bottom of the group is the least reactive halogen among them all.
8.
The electron configuration of calcium is
Correct Answer
2.8.8.2
2,8,8,2
Explanation
The electron configuration of an atom represents the arrangement of electrons in its energy levels. In the case of calcium, it has 20 electrons. The electron configuration is written as 2.8.8.2, indicating that the first energy level (n=1) has 2 electrons, the second energy level (n=2) has 8 electrons, the third energy level (n=3) has 8 electrons, and the fourth energy level (n=4) has 2 electrons. Another way to represent the electron configuration is by listing the number of electrons in each energy level, which is 2,8,8,2 for calcium.
9.
The electron configuration of the least reactive alkali metal is
Correct Answer
2.1
2,1
Explanation
The electron configuration of an atom represents the arrangement of electrons in its energy levels or shells. The least reactive alkali metal refers to the alkali metal with the highest ionization energy, which means it requires the most energy to remove an electron from its outermost shell. The electron configuration "2.1,2,1" indicates that the first energy level (shell) has 2 electrons, the second energy level has 1 electron, and the third energy level has 2 electrons. This configuration corresponds to the alkali metal lithium (Li), which has a relatively high ionization energy compared to other alkali metals, making it the least reactive among them.
10.
Nitrogen is found in nature in two different isotopes. N-14 and N-15 with respective abundances of 99.63% and 0.37% respectively. The average atomic mass of Nitrogen is
Correct Answer
14.00
14.004
14.0037
Explanation
The average atomic mass of Nitrogen is calculated by taking into account the abundance of each isotope and its respective atomic mass. In this case, N-14 has an abundance of 99.63% and an atomic mass of 14.00, while N-15 has an abundance of 0.37% and an atomic mass of 15.00. By multiplying the abundance of each isotope by its atomic mass and summing them up, we get the average atomic mass of Nitrogen. Therefore, the correct answers are 14.00, 14.004, and 14.0037.