Unit 2: Periodic Table & Periodic Trends

The Russian scientist, Dmitri Mendeleev, noticed that by arranging the elements known at his time in order of increasing _______________, similarities in the chemical properties appeared at regular intervals.

• atomic number

• atomic mass

• group number

• period number

What is the most active element in group 17?

• iodine, I

• bromine, Br

• chlorine, Cl

• fluorine, F

How does an atom’s ability to attract electrons in a chemical compound change as you move left to right across period 4 from cobalt, Co, to bromine, Br?

• It does not change

• It can’t be predicted

• It increases

• It decreases

Which element is the most electronegative?

• fluorine, F

• sodium, Na

• neon, Ne

• cesium, Cs

Which of the following elements has the greatest electronegativity?

• chlorine, Cl

• sodium, Na

• magnesium, Mg

• bromine, Br

A measure of the ability of an atom to attract electrons from another atom in a chemical compound is called

a) c)

b) d)

• ionization energy

• electronegativity

• electron configuration

• electron affinity

Which of the following has the largest second ionization energy?

• magnesium, Mg

• sodium, Na

• phosphorus, P

• aluminum, Al

As you move across the second period of the periodic table, ________

• ionization energy decreases

• atomic radius decreases

• ionization energy increases

• both atomic radius decreases and ionization energy increases

Which of the following factors contributes to the increase in ionization energy going across the period from

left to right?

• an increase in the shielding effect

• an increase in the number of energy levels

• fewer electrons in the outermost energy level

• an increase in the number of protons, smaller atomic radius

The energy required to remove an electron from an atom is called

• electron energy

• electronegativity

• ionization energy

• valence energy