BMST - Basic Math and Science Atomic Structure and Bonding Questions and Answers — Questions and Answers
Question 1: An atom of an element is defined by which fundamental quantity?
- The number of neutrons in the nucleus
- The total number of protons and neutrons
- The number of protons in the nucleus (Correct answer)
- The number of electrons in the valence shell
Correct answer: The number of protons in the nucleus
The atomic number (Z) of an element is equal to the number of protons in the nucleus of an atom of that element. This number uniquely identifies a chemical element and determines its chemical properties.
Question 2: A scientist is studying two atoms. Atom A has 17 protons and 18 neutrons. Atom B has 17 protons and 20 neutrons. Which term best describes the relationship between Atom A and Atom B?
- They are ions of the same element.
- They are isotopes of the same element. (Correct answer)
- They are different elements.
- They are allotropes of the same element.
Correct answer: They are isotopes of the same element.
Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons. Since both atoms have 17 protons, they are both atoms of chlorine, but they have different numbers of neutrons (18 and 20), making them isotopes.
Question 3: Which of the following describes the formation of an ionic bond?
- Two nonmetal atoms sharing a pair of electrons to achieve stability.
- A metal atom transferring one or more valence electrons to a nonmetal atom. (Correct answer)
- A lattice of positive ions immersed in a 'sea' of delocalized electrons.
- Two atoms with identical electronegativity sharing electrons equally.
Correct answer: A metal atom transferring one or more valence electrons to a nonmetal atom.
An ionic bond is a type of chemical bond formed through the electrostatic attraction between two oppositely charged ions. It is formed by the complete transfer of one or more valence electrons from a metal atom to a nonmetal atom.
Question 4: Which subatomic particle has a positive charge and is located within the nucleus of an atom?
- Electron
- Positron
- Neutron
- Proton (Correct answer)
Correct answer: Proton
A proton is a subatomic particle found in the nucleus of every atom, carrying a positive electric charge. Electrons are negatively charged and orbit the nucleus, while neutrons are in the nucleus but have no charge.
Question 5: A magnesium atom (Mg) readily loses two electrons to form an ion, while a chlorine atom (Cl) readily gains one electron to form an ion. What is the chemical formula for the ionic compound magnesium chloride?
- MgCl
- Mg2Cl
- MgCl2 (Correct answer)
- Mg2Cl2
Correct answer: MgCl2
Magnesium forms a Mg²+ ion by losing two electrons. Chlorine forms a Cl⁻ ion by gaining one electron. To form a neutral compound, the total positive charge must balance the total negative charge. Therefore, two chloride ions are needed to balance the charge of one magnesium ion, resulting in the formula MgCl₂.
Question 6: The ability of metals to conduct electricity is a direct result of which type of bonding?
- Ionic bonding
- Metallic bonding (Correct answer)
- Nonpolar covalent bonding
- Polar covalent bonding
Correct answer: Metallic bonding
Metallic bonding is characterized by a 'sea' of delocalized electrons that are free to move throughout the metal's structure. This mobility of charged particles (electrons) allows metals to be excellent conductors of electricity.
BMST - Basic Math and Science Atomic Structure and Bonding Questions and Answers
An atom of an element is defined by which fundamental quantity?