8th Grade Chemistry Test: Ultimate Quiz

Explanation
Hydrogen is located in Group 1 of the periodic table because it has only one electron in its outermost energy level, making it similar to the alkali metals in that group even though it is a gas. It shares similar properties with the alkali metals, such as being highly reactive and having a tendency to lose its single electron to form a positive ion. Therefore, hydrogen is classified in Group 1 of the periodic table.

Explanation
Chlorine has an atomic number of 17, which represents the number of protons in its nucleus. The atomic mass of chlorine is approximately 35.5, and chlorine-35 is a common isotope. Since the atomic mass is the sum of protons and neutrons, we can subtract the atomic number from the atomic mass to find the number of neutrons. Therefore, 35 - 17 = 18 neutrons are present in 1 atom of chlorine.

Explanation
Copper is an element with atomic number 29, which means it has 29 protons in its nucleus. In a neutral atom, the number of electrons is equal to the number of protons. Therefore, there are 29 electrons in 1 neutral atom of copper.

Explanation
Oxygen is best described as a nonmetal because it is a chemical element that lacks metallic properties. Nonmetals are typically poor conductors of heat and electricity, have low melting and boiling points, and tend to gain or share electrons in chemical reactions. Oxygen fits these characteristics as it is a gas at room temperature, does not conduct electricity, and readily forms covalent bonds with other elements.

Explanation
The atomic number for an element represents the number of protons in its nucleus. Hydrogen has an atomic number of 1, indicating that it has one proton. This is the smallest possible atomic number, as hydrogen is the lightest element on the periodic table.

Explanation
Chlorine has three electron shells. The electron shells are the energy levels or orbitals where electrons are found in an atom. Chlorine has an atomic number of 17, which means it has 17 electrons. These electrons are distributed among the three electron shells, with the first shell holding a maximum of 2 electrons, the second shell holding a maximum of 8 electrons, and the third shell holding the remaining 7 electrons. Therefore, chlorine has three electron shells. You can easily tell that chlorine has three electron shells because it is in the third row of the period table in the p-block.

Explanation
Oxygen has two electron shells. The electron shells are energy levels or orbits where electrons are found around the nucleus of an atom. The first shell can hold a maximum of 2 electrons, while the second shell can hold a maximum of 8 electrons. Since oxygen has 8 electrons, it fills the first shell with 2 electrons and the second shell with 6 electrons. Therefore, the correct answer is 2. You can easily tell that oxygen has two electron shells since oxygen is in the second row of the period table in the p-block.

Explanation
The reaction between an acid and a base is called neutralization. This process involves the combination of hydrogen ions from the acid and hydroxide ions from the base, resulting in the formation of water and a salt. The term "neutralization" is used because the resulting solution is neither acidic nor basic, but rather neutral in nature. This reaction is commonly used in various applications, such as in the production of fertilizers, pharmaceuticals, and household cleaning products.

Explanation
The neutral oxygen atom has 6 valence electrons. Valence electrons are the electrons in the outermost energy level of an atom, and they are responsible for the atom's chemical properties and ability to form bonds with other atoms. In the case of oxygen, the electron configuration is 1s2 2s2 2p4, meaning there are 2 electrons in the 1s orbital, 2 electrons in the 2s orbital, and 4 electrons in the 2p orbital. The 2s and 2p orbitals are considered the valence orbitals, so there are a total of 6 valence electrons in a neutral oxygen atom.

Explanation
Cellular Respiration is the correct answer because it is the chemical process that occurs in cells to release energy. During respiration, glucose is broken down in the presence of oxygen to produce ATP (adenosine triphosphate), which is the energy currency of the cell. This process occurs mainly in the mitochondria of the cell and is essential for the survival and functioning of all living organisms.