Question
How many electrons will be gained or lost when the element with electron configuration \(1s^2\) \(2s^2\) \(2p^3\) forms an ionic bond?
A. Two electrons lost
B. Two electrons gained
C. Three electrons lost
D. Three electrons gained
▶️Answer/Explanation
Markscheme: D
To determine how many electrons are gained or lost during the formation of an ionic bond, we need to look at the electron configuration of the element.
The given electron configuration is \(1s^2 2s^2 2p^3\). The outermost electron shell is the second shell, and there are a total of five electrons in the outer shell (\(2s^2 2p^3\)).
Elements tend to gain or lose electrons to achieve a stable, noble gas electron configuration. In this case, the element can gain three electrons to achieve the electron configuration of the noble gas neon (\(1s^2 2s^2 2p^6\)). Therefore, the correct answer is:
D. Three electrons gained.
Question
Which substance is likely to have an ionic lattice structure at 298K and 100kPa?
▶️Answer/Explanation
Markscheme : D
The characteristics that suggest an ionic lattice structure are a high melting point and the ability to conduct electricity in a molten state (liquid) or when dissolved in water. Ionic compounds generally have high melting points due to the strong electrostatic forces holding the ions together in a lattice structure.
So, based on the provided information, the substance likely to have an ionic lattice structure is the one with a high melting point and the ability to conduct electricity in a liquid state.
Therefore, the correct choice is:
High melting point & Conducts electricity in a liquid state? – This combination suggests an ionic lattice structure.
So, the correct answer is “high & yes”.
Question
Which bonds cause the boiling point of water to be significantly greater than that of hydrogen sulfide?
A. London (dispersion)
B. Covalent
C. Ionic
D. Hydrogen
Answer/Explanation
Markscheme
D
Examiners report
Question
What is the formula of ammonium phosphate?
A. (NH3)3PO4
B. (NH4)3PO4
C. (NH4)2PO4
D. (NH3)2PO3
Answer/Explanation
Markscheme
B
Examiners report
Question
Which substance is most likely to be ionic?
| Melting point | Solubility in hexane | Electrical conductivity of solid |
A | High | Low | High |
B | Low | Low | Low |
C | Low | High | Low |
D | High | Low | Low |
Answer/Explanation
Ans: D