BMST - Basic Math and Science Atomic Structure and Bonding Questions and Answers 5 — Questions and Answers
Question 1: Which model of the atom describes electrons as existing in a probability cloud or orbital rather than a fixed orbit?
- Dalton's solid sphere model
- Thomson's plum pudding model
- Bohr's planetary model
- Quantum mechanical model (Correct answer)
Correct answer: Quantum mechanical model
The quantum mechanical model uses orbitals — regions of probability — to describe where electrons are likely to be found.
Question 2: Sodium (Na) has an atomic number of 11. How many electrons are in its outermost shell?
- 1 (Correct answer)
- 2
- 3
- 8
Correct answer: 1
Sodium's electron configuration is 2-8-1, placing one electron in the third (outermost) shell.
Question 3: Double covalent bonds involve the sharing of how many electrons between two atoms?
- 2
- 4 (Correct answer)
- 6
- 8
Correct answer: 4
A double bond consists of two shared pairs of electrons, totaling 4 electrons between the two atoms.
Question 4: Which of the following pairs would most likely form an ionic compound?
- Carbon and hydrogen
- Oxygen and sulfur
- Sodium and chlorine (Correct answer)
- Nitrogen and oxygen
Correct answer: Sodium and chlorine
Sodium is a metal and chlorine is a nonmetal; large electronegativity differences between metals and nonmetals favor ionic bonding.
Question 5: An element has 17 protons. It gains one electron to become an ion. What is the charge of this ion?
- +1
- +2
- -1 (Correct answer)
- -2
Correct answer: -1
Gaining one electron adds a negative charge, making the ion a 1- (chloride) ion.
Question 6: What does electronegativity measure?
- The energy needed to remove an electron from a gaseous atom
- An atom's ability to attract shared electrons in a chemical bond (Correct answer)
- The total number of electrons in the outermost shell
- The force between two oppositely charged ions
Correct answer: An atom's ability to attract shared electrons in a chemical bond
Electronegativity quantifies how strongly an atom in a bond pulls the shared electron pair toward itself.
Question 7: Which of the following molecules contains a triple covalent bond?
- H₂O
- O₂
- N₂ (Correct answer)
- CO₂
Correct answer: N₂
N₂ has a triple bond (three shared pairs of electrons) between the two nitrogen atoms.
BMST - Basic Math and Science Atomic Structure and Bonding Questions and Answers 5
Which model of the atom describes electrons as existing in a probability cloud or orbital rather than a fixed orbit?