Advertisements
Advertisements
प्रश्न
In the following set of element, one element does not belong to the set. Select this element and state why it does not belong:
Calcium, Magnesium, Sodium, Beryllium
उत्तर
In the given set of elements, i.e., calcium, magnesium, sodium and beryllium, sodium does not belong to the set. This is because sodium is a group 1 element and the remaining three elements belong to group 2. Elements of the same group show similar chemical properties.
APPEARS IN
संबंधित प्रश्न
The atomic masses of three elements A, B and C having similar chemical properties are 7, 23 and 39, respectively.
- Calculate the average atomic mass of elements A and C.
- Compare the average atomic mass with atomic mass of B.
- What could the elements A, B and C be?
The position of eight elements in the Modern Periodic Table is given below where atomic numbers of elements are given in the parenthesis.
| Period No. | ||
| 2 | Li(3) | Be(4) |
| 3 | Na(11) | Mg(12) |
| 4 | K(19) | Ca(20) |
| 5 | Rb(37) | Sr(38) |
(i) Write the electronic configuration of Ca.
(ii) Predict the number of valence electrons in Rb.
(iii) What is the number of shells in Sr?
(iv) Predict whether K is a metal or a non – metal.
(v) Which one of these elements has the largest atom in size?
(vi) Arrange Be, Ca, Mg and Rb in the increasing order of the size of their respective atoms.
Given alongside is a part of the periodic table. As we move vertically downward from Li to fr?
| Li | Be |
| Na | |
| K | |
| Rb | |
| Cs | |
| Fr | |
| rA | Ra |
What happens to the size of atoms?
Five elements A, B, C, D and E have atomic numbers of 2, 3, 7, 10 and 18 respectively. The elements which belong to the same period of the periodic table are:
(a) A, B, C
(b) B, C, D
(c) A, D, E
(d) B, D, E
State the trends in physical properties on moving down the group. Give an example to illustrate.
An element X belong to 4th period and 17th group, state.
name of the element.
Fill in the blank:
on moving from right to left in the second period, the number of valence electrons……….
First ionization enthalpy of two elements X and Y are 500 KJ mol-1 and 375 KJ mol-1 respectively. Comment about their relative position in a group as well as in a period.
What is meant by a group in the periodic table?
Name or state following with reference to the element of the first three periods of the periodic table.
The valency of the element in period 3 having atomic number 17.
