Question 1

What is atomic radius?

Accepted Answer

The distance between an atom's nucleus and its outermost electron

Question 2

What are the trends for atomic radius?

Accepted Answer

Down: increases (more electron shells)

Right: decreases (due to more valence electrons causing stronger attraction)

Question 3

What is electron shielding?

Accepted Answer

Outer electrons are shielded from the attractive protons in the nucleus by the repulsive inner electrons

Question 4

What is ionic radius?

Accepted Answer

The distance from the nucleus to the outermost electron of an ion

Question 5

What is electronegativity?

Accepted Answer

A measure of an atom's tendency to attract shared electrons when it forms a chemical bond

Question 6

What are the trends for electronegativity?

Accepted Answer

Down: decreases (greater atomic radius causes lower electronegativity)

Right: increases (the more electrons in the valence shell, the easier it is to gain another)

Question 7

What is ionization energy?

Accepted Answer

The minimum amount of energy required to remove an electron from an atom or molecule

Question 8

What is first ionization energy?

Accepted Answer

The energy required to remove the loosest electron from an atom or molecule

(each removal is harder than the last, so 2nd ionization energy () > 1st ionization energy ())

Question 9

What are the trends for ionization energy?

Accepted Answer

Down: decreases (due to electron shielding)

Right: increases (valence shell becomes more stable)

Question 10

What is electron affinity?

Accepted Answer

The energy released when an electron is added to the atom to form an anion

(an atom's likelihood of gaining an electron)

Question 11

What is the difference between electron affinity and electronegativity?

Accepted Answer

Electronegativity is the tendency to attract electrons from other elements

Electron affinity is the energy released when an electron is added to an atom

Question 12

What are the trends for electron affinity?

Accepted Answer

Down: decreases (caused by increase in atomic radius)

Right: increases (caused by decrease in atomic radius)

Question 13

What is effective nuclear charge ()?

Accepted Answer

The net positive charge valence electrons experience

(increase in atomic number (# protons) causes this to go up; increase in shielding electrons causes this to go down)

Question 14

How do you calculate effective nuclear charge?

Accepted Answer

(Effective nuclear charge) = (atomic number) - (# of shielding electrons)

Question 15

What are the trends for effective nuclear energy?

Accepted Answer

Down: constant (atomic number and shielding electrons both increase)

Right: increase (atomic number increases, but shielding electrons stay the same)

Question 16

Why do electrons in the same group have similar properties and reactivity?

Accepted Answer

They have the same number of valence electrons

( and  are both brittle because Na and K are in the same group)

Periodic Trends, AP Chemistry Flashcards