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प्रश्न
An element Z has atomic number 16. Answer the following questions on Z:
1) State the period and group to which Z belongs
2) Is Z a metal or a non-metal?
3) State the formula between Z and hydrogen
4) What kind of a compound is this?
उत्तर
An element Z having atomic number 16 is Sulphur
1) Sulphur belongs to Period 3 and Group 16.
2) Sulphur is a non-metal.
3) Two hydrogen atoms combine with one sulphur atom to form hydrogen sulphide (H2S) gas
4) Hydrogen sulphide is the chemical compound with the formula H2S. It is a colourless gas with the characteristic foul odour of rotten eggs; it is heavier than air, very poisonous, corrosive, flammable and explosive.
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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 atomic numbers of three elements A, B and C are 12, 18 and 20 respectively. State, giving reason, which two elements will show similar properties.
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.
How does the tendency to gain electrons change as we go down in group 17 of the periodic table? Why does it change this way?
In which part of a group would you separately expect the elements to have the greatest metallic character
Explain
Size of atom changes when it loses or gain electron
In the above table, H does not represent hydrogen.Some elements are given in their own symbol and position in the periodic table while others are shown with a letter. With refrence to the table answer the following questions.
1. Identify the most electronegative element.
2. Identify the most reactive element of Group I.
3. Identify the element from Period 3 with least atomic size.
4. How many valence electrons are present in Q?
5. Which element from group 2 would have the least ionisation energy?
6. Identify the noble gas of the fourth period.
7. In the compound between A and H, what type of bond would be formed and give its molecular formula.
An element belongs to the third period and Group IIIA (13) of the periodic table. State: if it is a metal or non-metal?
An element A has 2 electrons in its fourth shell. State:
is it a metal or non-metal
Name or state following with reference to the elements of the first three periods of the periodic table.
A metalloid in period 2 and in period 3.
