Study Guide for Periodic Table Trends

Study guide for periodic table trends.

1. A. By referring to electron arrangements and using information from Table 8 of the Data booklet, explain the difference in radius for each of the following pairs:

(i) Na and Na+

(ii) Na+ and F-.

B. By referring to atomic structure and using information from table 6 of the data booklet, explain the difference in melting point for each of the following pairs:

(i) Na and Mg

(ii) F2 and Cl2 Cl>F because more electrons and greater intermolecular van der waal’s forces

2. (a) State and explain the term electronegativity.

(b). state and explain the trend in electronegativity across period 3 from Na to Cl.

- (c ) explain why Cl2 rather than Br2 would react more vigorously with the solution of I

3. Define the following terms

(i) Atomic number:

(ii) Mass number:

4. Explain the following statements.

The first ionization energy of sodium is

(i) Less than that of magnesium.

(ii) Greater than that of potassium

b. The electronegativity of chlorine is higher than that of sulfur.

5. (a) nitrogen is found in period 2 and group 5 of the periodic table.

(i) distinguish between the terms period and group :

(ii) state the electron arrangement of nitrogen and explain why it is found in period 2 and group 5 of the periodic table

(b) Table 8 of the data booklet gives the atomic and ionic radii of elements. State and explain the difference between

(i) the atomic radius of nitrogen and oxygen

(ii) tha atomic radius of nitrogen and phosphorus:

(iii) The atomic and ionic radius of nitrogen

6. Explain the following statements: A. The first ionization energy of sodium is

(I) Less that magnesium:

(II) Greater than potassium:

B. the electronegativity of chlorine is higher than that of sulfur.

7. 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.

(b) (i) explain how the first ionization energy of k compares with that of Na and Ar.

(II)explain the difference between the first ionization energies of Na and Mg.

(iii) Suggest why more energy is needed to remove an electron from Na+ than from Mg+.

8. Explain why

(i) The first ionization energy of magnesium is lower than that of fluorine?

(ii) Magnesium has a higher melting point than sodium?.

9. Which is related to the number of electrons in the outer main level of the elements form the alkali metals to the halogens?

I. GROUP NUMBER

II. PERIOD NUMBER

A. I only

B. II only

C. Both I and II

D. Neither I nor II.

10. Which pair of elements reacts more readily?

a. Li + Br2 b. Li + Cl2 c. K + Br2 d. K +Cl2

11. Which of the following properties of the halogens increase from F to I?

I. ATOMIC RADUIS II. MELTING POINT

III. ELECTRONEGATIVITY

A. I ONLY

B. I AND II ONLY

C. I AND III ONLY

D. I, II AND III

12. Element X is in group 2 and element Y is in group 7, of the periodic table. Which ions will be present in the compound formed when X and Y react together?

a. X+ and Y-

b. X2+ and Y –

c. X + and Y 2-

d. X2- and Y +

13. For which element are the group number and the period number the same?

14. Which of the physical properties below decrease with increasing atomic number for both the alkali metals and the halogens?

I. ATOMIC RADIUS II. IONIZATION ENERGY

II. MELTING POINT a. I only b. II only c. III only d. I and III only

15. Rubidium is an element in the same group of the periodic table as lithium and sodium. It is likely to be a metal which has a

a. High melting point and reacts slowly with water.

b. High melting point and reacts vigorously with water.

c. Low melting point and reacts vigorously with water. d. Low melting point and reacts slowly with water.

16. 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+, Ar d. Ar, Cl- K+

17. What increases in equal steps of one from left to right in the periodic table for the elements lithium to neon? a. The number of occupied electron energy levels b. The number of neutrons in the most common isotope c. The number of electrons in the atom d. The atomic mass

18. Which two elements react most vigorously with each other a. Chlorine and lithium b. Chlorine and potassium c. Iodine and lithium d. Iodine and potassium

19. Which factors lead to an element having a low value of first ionization energy?

I. Large atomic radius III high nuclear charge

II. High number of occupied energy levels

a. I and II only

b. I and III only

c. II and III only

d. I , II and III

20. Which statement about electronegativity is correct? a. Electronegativity decreases across the period b. Electronegativity increases down the group c. Metals generally have lower electronegativity values than nonmetals. d. Noble gases have the highest electronegativity values.

21. Which statement is correct for a periodic table?

a. Ionization energy increases from Li to Cs.

b. Melting point increases from Li to Cs.

c. Ionization energy increases from F to I

d. Melting point increases from F to I.

22. Which of the following statements are correct?

I. The melting points decrease from LiCs for the alkali metals

II. The melting points increase from FI for the halogens

III. The melting points decrease from NaAr for the period 3 elements a. I and II only b. I and III only c. II and III only d. I, II and III

23. Which properties decrease in value when descending group I?

I. Atomic radius

II. Ionization energy

III. Electronegativity a. I and II only b. I and III only c. II and III only d. I, II and III

24. The ionization energies of three consecutive elements in the periodic table are 1680, 2080 and 494 k? mol-1 respectively. Which of the following shows the elements with these values?

a. O F Ne

b. F Ne Na

c. Ne Na Mg

d. Na Mg Al 25. Analytical chemists can detect amounts of amino acids as small as 2.0 x 10 -21 mol of a substance. How many molecules does this represent?

a. 2.0 x 10 -21

b. 1.2 x 103

c. 6.0 x 1023

d. 3.0 x 10 44

26. In what order are the elements listed in the periodic table?

a. In order of relative atomic mass

b. In order of reactivity

c. In order of nuclear charge

d. In order of electronegativity

The graph shows the trend in a physical property down group 7 in the periodic table

27. What is the physical property?

a. Atomic radius

b. Electronegativity

c. Density

d. Melting point

28. Which is the best definition of electronegativity?

a. Electronegativity is the energy required for a gaseous atom to gain an electron.

b. Electronegativity is the attraction of an atom for a bonding pair of electrons.

c. Electronegativity is the attraction between the nucleus and the valence electrons of an atom.

d. Electronegativity is the ability of an atom to attract electrons from another atom.

29. Which sample has the greatest mass?

a. 6.0 x 1025 molecules of hydrogen

b. 5.0 mol of neon atoms c. 1.2 x 1024 atoms of silver

d. 1.7 x 102 grams of iron

30. Which is the correct definition of the mass number of an atom?

a. The total mass of neutrons and protons in the nucleus of the atom

b. The total mass of neutrons, protons, and electrons in the atom

c. The number of protons in the nucleus of the atom

d. The total number of neutrons and protons in the nucleus of the atom.

31. Which statement describes the trends of electronegativity values in the periodic table?

a. Values increase from left to right across a period and increase down a group.

b. Values increase from left to right across a period and decrease down a group.

c. Values decrease from left to right across a period and increase down a group.

d. Values decrease from left to right across a period and decrease down a group.

32. Which statement is correct for all elements in the same period?

a. They have the same number of electrons in the highest occupied energy level.

b. They have the same chemical reactivity.

c. They have the same number of occupied energy levels.

d. They have the same number of neutrons.

33. The graph o f the first ionization energy plotted against atomic number for the first twenty elements show periodicity

(I) Define the term first ionization energy and state what is meant by the term periodicity?

(II) State the electron arrangement of argon and explain why the noble gases, helium, neon and argon show the highest first ionization energies for their respective periods. (III) A graph of atomic radius plotted against atomic number shows that the atomic radius secreases across the period. Explain why chlorine has a smaller atomic radius than sodium.

(IV) Explain why a sulfide ion, S2- is larger than a chloride ion, Cl-.

(V) Explain why the melting point of the Group 1 metals(LiCs) decrease down a group whereas the melting points of the group 7 elements(fI) increase down the group.