Evgeny DimitrovIB1 Chemistry SL

Periodicity Review Questions

1. Which factors lead to an element having a low value of first ionization energy?I large atomic radiusII high number of occupied energy levelsIII high nuclear charge

A. I and IIB. I and III onlyC. II and III onlyD. I, II, III2. Which property decreases down group 7 in the periodic table?A. Atomic radiusB. ElectronegativityC. Ionic radiusD. Melting Point3. Which equation represents the first ionization energy of fluorine?A. F(g)+e-→F-

(g)

4. Which statement about electronegativity is correct?A. Electronegativity decreases across a period.B. Electronegativity increases down a group.C. Metals generally have lower electronegativity values than non-metals.D. Noble gases have the highest electronegativity values.

5. A potassium atom has a larger atomic radius than a sodium atom. Which statement about potassium correctly explains the difference?A. It has a larger nuclear charge.B. It has a lower electronegativity.C. It has more energy levels occupied by electrons.D. It has a lower ionization energy.

6. When the following species are arranged in order of increasing radius, what is the correct order?A. Cl-, Ar, K+

B. K+, Ar, Cl-

C. Cl-, K+, ArD. Ar, Cl-, K+

Evgeny DimitrovIB1 Chemistry SL

7. Which properties are typical of most non-metals in period 3 (Na to Ar)?I They form ions by gaining one or more electrons.II They are poor conductors of heat and electricityIII They have high melting points

A. I and II onlyB. I and III onlyC. II and III onlyD. I, II and III

8. The compounds Na2o, Al2O3 and SO2 respectively areA. Acidic, amphoteric and basicB. Amphoteric, basic and acidicC. Basic, acidic, amphotericD. Basic, amphoteric and acidic9. (i) Explain how the first ionization energy of K compares with that of Na and Ar.

K has a higher value of first ionization energy than Na. And Ar has the highest one from all three of them. (ii) Explain the difference between the first ionization energy of Na and Mg.Mg has a higher ionization energy. Mg’s electron shell has more electron than Na and requires more energy to remove one electron rather than both of Mg. (iii) Suggest why much more energy is needed to remove an electron form Na+ than from Mg+There is more energy needed because Mg removes two valence electrons and Na only removes one. Na needs 496 units to remove one electron, whereas Mg needs 738 to remove 2, so more energy is needed to remove one electron from Na, rather than from Mg.

10. Table 6 of the Data Booklet lists melting points of the elements. Explain the trend in the melting points of the alkali metals, halogens and period 3 elements.From Li to Cs the melting points decrease due to the increase in atomic radius.From F to I the melting points increase due to the increase of atomic radius.Period 3 from Na to Al they increase and then to Cl they decrease.

11. (a) State the meaning of the term electronegativity.The measure for the ability of the atoms of one element to attract electrons when bonded covalently to atoms of another element. (b) State and explain the trend in electronegativity across period 3 from Na to Cl.The trend of electronegativity is that it increases from Na to Cl due to the increase in the number of valence electrons in the third electron shell going from Na to Cl.(c) Explain why Cl2 rather than Br2 would react more vigorously with a solution of I-. Cl2 has a bigger reactivity value than Br2. It is more reactive, so when Cl2 has a reaction with KI:

Evgeny DimitrovIB1 Chemistry SL

Cl2+2KI →2KCL+I2