BMST - Basic Math and Science Atomic Structure and Bonding Questions and Answers 2 — Questions and Answers
Question 1: What subatomic particle has a negative charge and orbits the nucleus?
- Electron (Correct answer)
- Proton
- Neutron
- Photon
Correct answer: Electron
Electrons carry a negative charge and are found in orbitals around the nucleus.
Atoms consist of three main subatomic particles: protons (positive charge, in nucleus), neutrons (no charge, in nucleus), and electrons (negative charge, orbiting the nucleus in energy levels). Electrons have a charge of -1 and a mass of approximately 1/1836 of a proton.
Question 2: How many electrons can the second energy level (n=2) hold?
- 8 (Correct answer)
- 2
- 18
- 32
Correct answer: 8
The formula 2n² gives the maximum electrons per level. For n=2: 2(4) = 8.
Each energy level can hold a maximum of 2n² electrons, where n is the principal quantum number. For the first level (n=1): 2(1)² = 2 electrons. For the second level (n=2): 2(2)² = 8 electrons. For the third level (n=3): 2(3)² = 18 electrons.
Question 3: What type of bond forms when atoms share electrons?
- Covalent bond (Correct answer)
- Ionic bond
- Metallic bond
- Hydrogen bond
Correct answer: Covalent bond
Covalent bonds form when two atoms share one or more pairs of electrons.
Covalent bonds form when atoms share electron pairs to achieve stable electron configurations. This typically occurs between nonmetal atoms with similar electronegativities. Ionic bonds involve electron transfer, metallic bonds involve a sea of delocalized electrons, and hydrogen bonds are weak intermolecular forces.
Question 4: What is the atomic number of an element?
- The number of protons in its nucleus (Correct answer)
- The total number of protons and neutrons
- The number of electron shells
- The mass of the atom in grams
Correct answer: The number of protons in its nucleus
The atomic number equals the number of protons, which defines the element.
The atomic number (Z) is the number of protons in an atom's nucleus. It defines the element: all carbon atoms have 6 protons (Z=6), all oxygen atoms have 8 protons (Z=8). In a neutral atom, the number of electrons equals the atomic number. The mass number (A) is the total of protons plus neutrons.
Question 5: Which of the following is an example of an ionic compound?
- NaCl (sodium chloride) (Correct answer)
- H₂O (water)
- CO₂ (carbon dioxide)
- CH₄ (methane)
Correct answer: NaCl (sodium chloride)
NaCl forms when sodium transfers an electron to chlorine, creating Na⁺ and Cl⁻ ions.
Ionic compounds form between metals and nonmetals through electron transfer. Sodium (a metal) loses one electron to become Na⁺, and chlorine (a nonmetal) gains that electron to become Cl⁻. The electrostatic attraction between these oppositely charged ions creates an ionic bond. Water, CO₂, and methane are all covalent compounds.
Question 6: What does the octet rule state?
- Atoms tend to gain, lose, or share electrons to have 8 valence electrons (Correct answer)
- All atoms must have exactly 8 protons
- Molecules must contain 8 atoms
- Chemical reactions always produce 8 products
Correct answer: Atoms tend to gain, lose, or share electrons to have 8 valence electrons
The octet rule describes atoms' tendency to achieve 8 electrons in their outermost shell for stability.
The octet rule states that atoms are most stable when they have 8 electrons in their valence (outermost) shell, resembling the electron configuration of noble gases. Atoms achieve this through ionic bonding (transferring electrons) or covalent bonding (sharing electrons). Exceptions include hydrogen (which follows the duet rule with 2 electrons) and some elements in the third period and beyond.
BMST - Basic Math and Science Atomic Structure and Bonding Questions and Answers 2
What subatomic particle has a negative charge and orbits the nucleus?