Periodic Trends

Which of the following elements has the smallest radius?

• Mg
• Al
• Si
• K

Which element in Period 2 has the greatest atomic radius?

• Be

• C

• Na

• Li

As you move across the periodic table from left to right, the atomic radius decreases.  This is because - 

• the number of protons increases, so attraction to electrons increases
• the number of energy levels increases
• the number of electrons increases
• the atomic mass increases

Ionization energy is...

• the energy required to add an electron to a specific atom
• how much energy it takes to remove an electron from an atom
• the energy required to shield the outer electrons from the nucleus
• a measure of the ability of an atom to attract electrons

Electronegativity __________ from left to right within a period and __________ from top to bottom within a group.

• decreases, increases

• increases, increases

• increases, decreases

• stays the same, increases

Francium (Fr) has the lowest ionization energy in Group 1 because - 

• it has the smallest number of valence electrons
• it has the greatest atomic mass
• it has the greatest number of protons, so it attracts its electrons the strongest
• its 1 valence electron is very far from the nucleus, so little energy is needed to remove it

Which has the greater EN: 
H or F?

• H
• F

Atoms that have a high electronegativity, _______________.

• give up their electrons more easily.
• hold on to their electrons more tightly.
• have more electron shells.

Which of the following sequences corresponds to a correct trend in ionization energy?

• Cl > S > P > Al
• Sr > Ca > Mg > Be
• Rb > K > Na > Li
• Rb > Sr > I > Xe

The ability of an atom to attract electrons in a bond is called

• Ionization energy

• electronegativity

• atomic radius

• proton affinity