Q. No.Property used by Mendeleev to classify the elements was:
1. Brightness
2. Atomic weight or mass
3. Number of isotopes
4. Lustre
1. Unniloctium
2. Ununoctium
3. Nilniloctinium
4. Ununoctinium
X and Y are respectively:
1. 14 and 7
2. 15 and 7
3. 16 and 7
4. 17 and 7
| List-I (IUPAC official name) |
List-II (IUPAC Symbol) |
||
| A. | Mendelevium | I. | Mt |
| B. | Meitnerium | II. | Mc |
| C. | Moscovium | III. | No |
| D. | Nobelium | IV. | Md |
| 1. | A-III, B-I, C-II, D-IV | 2. | A-IV, B-II, C-I, D-III |
| 3. | A-IV, B-I, C-II, D-III | 4. | A-I, B-IV, C-II, D-III |
The group number, number of valence electrons, and valency of an element with atomic number 15,
respectively, are:
1. 16, 6 and 3
2. 15, 6 and 12
3. 16, 5 and 2
4. 15, 5 and 3
Among the following, the elements that can show covalency greater than 4 is/are:
(a) Be
(b) P
(c) S
(d) B
Choose the correct option
1. (a), (d)
2. (b), (c)
3. (c), (d)
4. (b), (d)
Incorrect statement among the following is-
1) Elements are classified into periods and groups
2) Elements with similar properties are placed in the same group
3) This makes the study of elements simpler
4) Elements are placed according to decreasing atomic number
1. \(N^{3-}, O^{2-}, F, Na \)
2. \(\mathrm{S}^{-2}, \mathrm{Cl}^{-}, \mathrm{K}^{+}, \mathrm{Ca}^{2+} \)
3. \(\mathrm{NH}_3, \mathrm{CH}_4, \mathrm{PF}_5, \mathrm{Na}^{+} \)
4. \(\mathrm{Ne}, \mathrm{Na}^{+}, \mathrm{F}, \mathrm{N}^{3-} \)
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