Tutorial 1B – PERIODIC TABLE

QUESTIONS

1. Naturally occurring chromium consists of four isotopes. It is 4.31% 2450Cr, mass = 49.946 amu, 83.76%

2452Cr, mass = 51.941 amu, 9.55% 24

53Cr, mass = 52.941 amu, and 2.38% 2454Cr, mass = 53.939 amu.

Calculate the atomic weight of chromium

2. Which electrons have the greatest influence on the properties of elements?

a. those electrons in s orbitalsb. those electrons in d orbitalsc. core electronsd. the outermost electronse. none of these

3. Of the following, which element does not match its designation?

(a) 38Sr representative metal(b) 49In representative nonmetal(c) 14Si metalloid(d) 42Mo d-transition metal(e) 90Th f-transition metal

4. Of the following, which periodic group(s) do not match their designation?

(a) d-transition metals IIIB - IIB(b) representative metals IA, IIA(c) noble gases VIIIB(d) alkaline earth metals IIA(e) halogens VIIA

5. ______ is a noble gas.

(a) 22Ti (b) 42Mo (c) 81Tl (d) 54Xe (e) 92U

6. ______ is an actinide.

(a) 22Ti (b) 42Mo (c) 81Tl (d) 36Kr (e) 93Np

7. What would be the outer electron configuration of group VIA (O, S, Se, . . .)?

(a) ns2np6 (b) ns2np2 (c) ns2np4 (d) np6 (e) ns0np6

8. Arrange in order of increasing atomic radiiAl, C, Si

9. Arrange in order of increasing ionization energy

1. Ar, Se, S2. As, Br, Sb.

10. Using the periodic table only, arrange the following ions in order of increasing ionic radius:

Br−, Se2−, Sr2+.

11. Given the following information for element E, identify the element’s group in the periodic table: The electron affinity of E is positive (doesn’t form a stable negative ion). The first Ionisation Energy is less than the second, which is very much less than the third. The element is in Group IIA.

12. A certain element is a metalloid that forms an acidic oxide with the formula R2O5. Identify the element.

13. Draw the Born-Haber cycle for the complex RX and calculate the Hfo for RX using the Born Haber Cycle.

Sublimation Energy R = 200 kJ/mol

Ionization Energy R = 480 kj/mol

Electron Affinity of X = -300 kJ/mol

Heats of Dissociation of X2 = 122 kJ/mol Cl2

Lattice Energy of RX = 898 kJ/mol