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Practice each question, then open the answer or worked solution.
Which one of the following elements exhibit a maximum number of valence electrons?
The answer is (d) P
Explanation:
Electronic configuration of Na, Al, Si and P are 2,8 1, 2,8,3,2,8,4, and 2,8,5 respectively. Valence electrons in Na, Al, Si and P are 1,3,4 and 5 Hence phosphorus has a maximum number of valence electrons.
Which of the following gives the correct increasing order of the atomic radii of O, F and N?
(a) O, F, N
(b) N, F, O
(c) O, N, F
(d) F, O, N
The answer is (d) F, O, N
Explanation:
Atomic radius increase as move from left to right across a period. (N7), O(8) and F(10) are in increasing order of atomic numbers.
Which among the following elements has the largest atomic radii?
The answer is (c) K
K has the largest atomic radii because atomic radii decrease from left to right along a period. This is because of the increase in nuclear charge which tends to pull the electron closer to the nucleus and reduces the size of the atom. Hence K has the largest atomic radii.
Which of the following elements would lose an electron easily?
The answer is (c) K
Explanation:
Na and K belong to the same group I and Magnesium and Calcium belongs to a group (II). Because K contains one electron in its outermost shell and the lowest ionisation energy, it can easily lose an electron.
Which of the following elements does not lose an electron easily?
Sodium has 1, magnesium has 2 and Aluminium has 3 electrons in its outermost shell whereas Fluorine has 7 electrons in its outermost shell hence Fluorine does not lose electron easily.
Which of the following are the characteristics of isotopes of an element?
(a) (i), (iii) and (iv)
(b) (ii), (iii) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)
The answer is (d) (ii) and (iv)
Explanation:
Elements with same atomic number but different atomic masses are known as isotopes. Isotopes same chemical properties but differ in their physical properties.
Arrange the following elements in the order of their decreasing metallic character Na, Si, Cl, Mg, Al
The answer is (b) Na >Mg >Al >Si > Cl
Explanation:
Na has 1, magnesium has 2 , aluminium has 3 and Chlorine has 7 electrons in its valence shells. Hence Sodium shows maximum metallic characters followed by Magnessium, aluminium and chlorine shows non-metallic properties.
Arrange the following elements in the order of their increasing nonmetallic character Li, O, C, Be, F
Li is on the left of in the 2nd period of modern periodic table followed by berrylium. Fluorine is at right next to Neon. Hence Fluorine shows maximum non-metallic characters followed by Oxygen, Berrylium, carbon and Lithium.
What type of oxide would Eka– aluminium form?
Answer is (c) E2O3
Three elements B, Si and Ge are
The answer is (c) metalloids