CRAM: Periodic Table

Question 2

Periodic Table

Answer 2

A structured arrangement of elements highlighting trends and properties based on increasing atomic number.

Question 3

Periodic Trends

Answer 3

Recurring patterns in element properties observed as you move across or down the periodic table.

Question 4

Effective Nuclear Charge (Zeff)

Answer 4

The net positive charge experienced by an electron, calculated as actual nuclear charge (Z) minus shielding effect (S).

Question 5

Atomic Radius

Answer 5

The distance from the nucleus to the outermost electron; decreases across a period and increases down a group.

Question 6

Ionic Radius

Answer 6

The size of an ion; cations are smaller than their neutral atoms, while anions are larger.

Question 7

Electronegativity

Answer 7

The ability of an atom to attract electrons in a chemical bond; increases across a period and decreases down a group.

Question 8

Ionization Energy

Answer 8

The energy required to remove an electron from an atom; increases across a period and decreases down a group.

Question 9

Electron Affinity

Answer 9

The energy change when an atom gains an electron; becomes more negative across a period and less negative down a group.

Question 10

Groups

Answer 10

Vertical columns on the periodic table where elements share the same number of valence electrons.

Question 11

Periods

Answer 11

Horizontal rows on the periodic table where elements share the same number of electron shells.

Question 12

Valence Electrons

Answer 12

The outermost electrons of an atom that determine its chemical reactivity and bonding.

Question 13

Group 18 (Noble Gases)

Answer 13

Elements with a full octet of valence electrons, making them stable and largely unreactive.

Question 14

Shielding Effect

Answer 14

The repulsion of valence electrons by inner electrons, reducing the effective nuclear charge felt by the outermost electrons.

Question 15

Atomic Radius Across a Period

Answer 15

Decreases due to increased nuclear charge pulling electrons closer to the nucleus.

Question 16

Atomic Radius Down a Group

Answer 16

Increases due to additional electron shells, increasing the distance from the nucleus.

Question 17

Ionization Energy Across a Period

Answer 17

Increases as nuclear charge increases, making it harder to remove an electron.

Question 18

Ionization Energy Down a Group

Answer 18

Decreases as electrons are farther from the nucleus and more easily removed.

Question 19

Electronegativity Across a Period

Answer 19

Increases due to greater nuclear charge attracting bonding electrons more strongly.

Question 20

Electronegativity Down a Group

Answer 20

Decreases as the nucleus is farther from bonding electrons.

Question 21

Electron Affinity Across a Period

Answer 21

Becomes more negative as atoms are more eager to gain electrons to achieve stability.

Question 22

Electron Affinity Down a Group

Answer 22

Becomes less negative as larger atoms have weaker attraction for additional electrons.

Question 23

Neon vs. Xenon

Answer 23

Both are noble gases with full octets, but neon has 2 electron shells while xenon has 5, affecting atomic size.

Question 24

Sodium vs. Argon

Answer 24

Both are in Period 3, but argon has a greater nuclear charge, resulting in a smaller atomic radius than sodium.

Question 25

Be vs. B Exception

Answer 25

Boron has lower ionization energy than beryllium because its 2p electron is less tightly bound than Be’s 2s electrons.

Question 26

Fluorine vs. Chlorine Electron Affinity

Answer 26

Chlorine has a higher magnitude of electron affinity than fluorine due to less electron repulsion in its outer shell.

Question 27

Trends in Periods

Answer 27

Properties change across periods due to increasing nuclear charge and decreasing atomic radius.

Question 28

Trends in Groups

Answer 28

Properties vary due to increasing electron shells and shielding effect down a group.

Question 29

Key Trend Comparison: Atomic Radius

Answer 29

Decreases across a period but increases down a group.

Question 30

Key Trend Comparison: Ionization Energy

Answer 30

Increases across a period but decreases down a group.

Question 31

Key Trend Comparison: Electronegativity

Answer 31

Increases across a period but decreases down a group.