List of practice Questions

The following data gives the distribution of total monthly household expenditure of 200 families of a village. Find the modal monthly expenditure of the families. Also, find the mean monthly expenditure :

Expenditure (in Rs)	Number of families
1000 - 1500	24
1500 - 2000	40
2000 - 2500	33
2500 - 3000	28
3000 - 3500	30
3500 - 4000	22
4000 - 4500	16
4500 - 5000	7

What is the significance of the terms - 'isolated gaseous atom' and 'ground state' while defining the ionization enthalpy and electron gain enthalpy?
Hint: Requirements for comparison purposes.

A copper wire has diameter 0.5 mm and resistivity of \(1.6×10^{–8} \ Ω m\). What will be the length of this wire to make its resistance 10 Ω? How much does the resistance change if the diameter is doubled?

The size of isoelectronic species - F^-, Ne and Na⁺is affected by

Anything that influences the valence electrons will affect the chemistry of the element. Which one of the following factors does not affect the valence shell?

Explain why cations are smaller and anions larger in radii than their parent atoms?

How does atomic radius vary in a period and in a group? How do you explain the variation?

What does atomic radius and ionic radius really mean to you?

Why do elements in the same group have similar physical and chemical properties?

Which element do you think would have been named by
(i) Lawrence Berkeley Laboratory
(ii) Seaborg's group?

Write the atomic number of the element present in the third period and seventeenth group of the periodic table.

Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

In terms of period and group where would you locate the element with Z =114?

If all the waste we generate is biodegradable, will this have no impact on the environment?

On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.

What is the basic difference in approach between the Mendeleev's Periodic Law and the Modern Periodic Law?

Which important property did Mendeleev use to classify the elements in his periodic table and did he stick to that?

What are the problems caused by the non biodegradable wastes that we generate?

The following table gives the literacy rate (in percentage) of 35 cities. Find the mean literacy rate.

Literacy rate (in %)	45 - 55	55 - 65	65 - 75	75 - 85	85 - 95
Number of cities	11	10	7	4	4

What is the basic theme of organisation in the periodic table?

A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent.

Number of Days	0 - 6	6 - 10	10 - 14	14 - 20	20 - 28	28 - 38	38 - 40
Number of Students	11	10	7	4	4	3	1

To find out the concentration of SO\(_2\) in the air (in parts per million, i.e., ppm), the data was collected for 30 localities in a certain city and is presented below:

Concentration of SO\(\bf{_2}\) (in ppm)

Frequency

0.00 - 0.04

0.04 - 0.08

0.08 - 0.12

0.12 - 0.16

0.16 - 0.20

0.20 - 0.24

4

9

2

4

2

A cross was made by Mendel with pea plant between violet flower (VV) in axial position (AA) and while flower (vv) in terminal position (aa). What ratio of white flowers (vv) phenotypically he had received in F2 generation?

Thirty women were examined in a hospital by a doctor and the number of heartbeats per minute were recorded and summarised as follows. Find the mean heartbeats per minute for these women, choosing a suitable method.

Number of heartbeats per minute	65 - 68	68 - 71	71 - 74	74 - 77	77 - 80	80 - 83	83 - 86
Number of boxs	2	4	3	8	7	4	2

The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is Rs 18. Find the missing frequency f.

Daily pocket	11 - 13	13 - 15	15 - 17	17 - 19	19 - 21	21 - 23	23 - 25
Number of workers	7	6	9	13	f	5	4