Periodic Trends (15 min)

The tendency of an atom to attract electrons is called...

• ionization energy
• electronegativity
• atomic radius
• ionic radius

Ionization energy is the amount of energy required to remove the electron that is closest to the nucleus.

• True
• False

The octet rule states that an atom will gain or lose electrons in order to have a full valence shell (usually 8).

• True

• False

An atom with more electrons than protons is called...

• cation
• anion
• neutral
• shielded

Why is this statement untrue?   A cation has a positive charge because it has gained electrons.

• Cations are negative.
• This would describe anions.
• A cation's positive charge is due to lost electrons.
• The statement is actually true.

Teaching point: An electron's actual position is unknown, so you can't actually measure radius from nucleus to valence electron. Instead, the distance between the nuclei of 2 atoms of the same element is measured and cut in half. Atomic radius is actually determined by...

• A measurement of distance from nucleus to outermost electron.

• Half of the measured distance between the nuclei of two atoms of the same element.

• Calculation based on the number of energy levels an atom has.

• Half of the diameter of the nucleus.

Which of the following elements would be smaller as an ion than as a neutral atom?

• Fluorine

• Phosphorus

• Iodine

• Lithium

Which of the following would have a larger ionic radius than atomic radius?

• Sodium

• Calcium

• Zinc

• Chlorine

Which of the following elements are in order from lowest electronegativity to highest?

• F, N, B, Li
• Ga, Si, O, He
• K, Al, C, F
• Mg, V, Mo, Os

Which of the following trends would be higher for noble gases than for alkali metals?

• atomic radius
• electronegativity
• ionization energy
• ionic radius