- Which of the following properties does not increase as you move from left to right across a period?
a) Electronegativity
b) Ionization energy
c) Atomic radius
d) Electron affinity
Answer: c) Atomic radius
Explanation: As we move from left to right across a period, atomic radius decreases due to the increase in effective nuclear charge, which pulls the electrons closer to the nucleus. Electronegativity, ionization energy, and electron affinity all increase across a period due to the stronger pull on the electrons.
- Which of the following elements has the most metallic character?
a) Calcium (Ca)
b) Magnesium (Mg)
c) Potassium (K)
d) Beryllium (Be)
Answer: c) Potassium (K)
Explanation: Metallic character increases down a group and decreases across a period. Potassium is farther down Group 1, making it more metallic than the other options.
- The electron affinity of which of the following elements is lowest?
a) Nitrogen (N)
b) Oxygen (O)
c) Phosphorus (P)
d) Sulfur (S)
Answer: a) Nitrogen (N)
Explanation: Nitrogen has a half-filled p-orbital, which is relatively stable. This makes it less favorable for nitrogen to accept an additional electron, leading to a lower electron affinity compared to oxygen, phosphorus, or sulfur.
- Which of the following elements exhibits the greatest tendency to lose electrons?
a) Fluorine (F)
b) Lithium (Li)
c) Sodium (Na)
d) Potassium (K)
Answer: d) Potassium (K)
Explanation: Potassium, being the largest atom among the alkali metals in this list, has a lower ionization energy and readily loses an electron to form a K⁺ ion.
- Which of the following is not a property of transition elements?
a) Formation of colored compounds
b) Formation of complex compounds
c) High reactivity with water
d) Variable oxidation states
Answer: c) High reactivity with water
Explanation: Transition elements typically have lower reactivity with water compared to alkali metals, which react vigorously with water. The other properties (colored compounds, complex formation, and variable oxidation states) are characteristic of transition elements.
- Which of the following halides has the strongest bond?
a) HF
b) HCl
c) HBr
d) HI
Answer: a) HF
Explanation: The bond strength of halides decreases as the size of the halogen atom increases. HF has the strongest bond because fluorine is the smallest halogen, resulting in a short and strong bond with hydrogen.
- Which of the following elements has the highest electronegativity?
a) Carbon (C)
b) Sulfur (S)
c) Hydrogen (H)
d) Nitrogen (N)
Answer: d) Nitrogen (N)
Explanation: Among the given elements, nitrogen is the most electronegative because it lies farther to the right and closer to the top of the periodic table compared to carbon, sulfur, and hydrogen.
- Which of the following trends is true for halogens?
a) Reactivity decreases down the group
b) Electronegativity increases down the group
c) Melting point decreases down the group
d) Atomic radius decreases down the group
Answer: a) Reactivity decreases down the group
Explanation: The reactivity of halogens decreases as you move down the group due to increasing atomic size and decreasing ability to gain an electron.
- The correct order of atomic radius is:
a) Na > K > Rb > Cs
b) Cs > Rb > K > Na
c) Rb > K > Na > Cs
d) Na > Cs > K > Rb
Answer: b) Cs > Rb > K > Na
Explanation: Atomic radius increases down a group. Cesium, being the farthest down Group 1, has the largest atomic radius, followed by rubidium, potassium, and sodium.
- Which element is most likely to form a negative ion?
a) Sodium (Na)
b) Fluorine (F)
c) Calcium (Ca)
d) Aluminum (Al)
Answer: b) Fluorine (F)
Explanation: Fluorine is the most electronegative element and has a strong tendency to gain an electron and form a negative ion (F⁻).
- Which of the following is the most electronegative group in the periodic table?
a) Alkali metals
b) Transition metals
c) Noble gases
d) Halogens
Answer: d) Halogens
Explanation: Halogens are the most electronegative group in the periodic table because they are one electron short of achieving a stable noble gas configuration.
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