Question
Consider the following elements: Be, Li, Na, Ca, K. Name the elements of (a) same group (b) same period.
✓
Answer
| Element | At. No. | Electronic distribution |
| Be | 4 | 2, 2 |
| Li | 3 | 2, 1 |
| Na | 11 | 2, 8, 1 |
| Ca | 20 | 2, 8, 8, 2 |
| K | 19 | 2, 8, 8, 1 |
In the second period (Be, Li) and in the fourth period (K, Ca).
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Similar questions
At constant temperature, the effect of change of pressure on the volume of a gas was as given below:
(a) Plot the following graphs
(b) Assuming that the pressure values given above are correct, find the correct measurement of the volume.
→| Pressure in atmosphere | Volume in liters |
| $0.20$ | $112$ |
| $0.25$ | $89.2$ |
| $0.40$ | $56.25$ |
| $0.60$ | $37.40$ |
| $0.80$ | $28.10$ |
| $1.00$ | $22.4$ |
- $P$ vs $V$
- $P$ vs $1/V$
- $PV$ vs $P$
(b) Assuming that the pressure values given above are correct, find the correct measurement of the volume.
Give its
(i) graphical representation,
(ii) mathematical expression
(iii) significance
(i) graphical representation,
(ii) mathematical expression
(iii) significance
(a) what do you understand by the following terms?
(b) Give one equation to explain the meaning of 6(a) (i), (ii) and (iii).
(b) Give one equation to explain the meaning of 6(a) (i), (ii) and (iii).
Match the following:
→| Compound | Formula |
| 1. Boric acid | i. $NaOH$ |
| 2. Phosphoric acid | ii. $SiO_2$ |
| 3. Nitrous acid | iii. $Na_2CO_3$ |
| 4. Nitric acid | iv. $KOH$ |
| 5. Sulphurous acid | v. $CaCO_3$ |
| 6. Sulphuric acid | vi. $NaHCO_3$ |
| 7. Hydrochloric acid | vii. $H_2S$ |
| 8. Silica (sand) | viii. $H_2O$ |
| 9. Caustic soda (sodium hydroxide) | ix. $PH_3$ |
| 10. Caustic potash (potassium hydroxide) | x. $CH_4$ |
| 11. Washing soda (sodium carbonate) | xi. $NH_3$ |
| 12. Baking soda (sodium bicarbonate) | xii. $HCl$ |
| 13. Lime stone (calcium carbonate) | xiii. $H_2SO_3$ |
| 14. Water | xiv. $HNO_3$ |
| 15. Hydrogen sulphide | xv. $HNO_2$ |
| 16. Ammonia | xvi. $H_3BO_3$ |
| 17. Phosphine | xvii. $H_3PO_4$ |
| 18. Methane | xviii. $H_2SO_4$ |
Draw diagrams representing the atomic structures of the following:
- Sodium atom
- Chlorine ion
- Carbon atom
- Oxygen ion
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Compare :
Sodium atom and sodium ion
Sodium atom and sodium ion
An element $X$ has $2$ electrons in its $M$ shell, it forms a bond with an element $Y$ which has $7$ electrons in its third orbit.
→- Write the formula of the compound formed.
- Which nearest inert gas electronic configuration will element $X$ and $Y$ acquire.
- Show by orbital diagram the formation of the compound between $X$ and $Y.$
$800 cm^3$ of gas is collected at 650 mm pressure. At what pressure would the volume of the gas reduce by $40 \%$ of its original volume, the temperature remaining constant?
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