1.7 Periodic Trends

• The atomic radius decreases as you move across a period.


  True
• The atomic radius increases as you move down a group in the periodic table.

  True
• The effective nuclear charge decreases as you move down a group.


  True
• Electronegativity increases as you move across a period.


  True
• Ionization energy decreases as you move down a group
• The effective nuclear charge decreases as you move across a period.

  False
• The effective nuclear charge decreases as you move down a group.


  True
• As you move across a period, the effective nuclear charge increases, making it harder to remove an electron.
• Understanding periodic trends is crucial for predicting the chemical behavior
• Electronegativity increases across a period.


  True
• Periodic trends are observed as you move across a period or down a group in the periodic table.group
• Electronegativity increases as you move across a period and decreases down a group.group
• The atomic radius decreases as effective nuclear charge increases across a period.increases
• Atomic radius increases as you move down a group
• Ionization energy increases as you move across a period.

  True
• Order the following properties based on their trends across a period from left to right:

  1️⃣ Atomic Radius

  2️⃣ Electronegativity

  3️⃣ Ionization Energy

  4️⃣ Electron Affinity
• The shielding effect remains constant across a period.

  True
• The atomic radius decreases across a period
• Order the following periodic properties from least to most negative across a period:

  1️⃣ Electron Affinity ||| Electronegativity ||| Ionization Energy
• Increased effective nuclear charge leads to a decrease in atomic radius.


  True
• As you move down a group, the shielding effect increases, leading to a larger atomic radius.


  True
• Increased effective nuclear charge across a period increases ionization energy.


  True
• A more negative electron affinity indicates a stronger attraction for electrons.


  True
• Increased effective nuclear charge across a period enhances electronegativity.


  True
• Why is understanding periodic trends crucial for predicting chemical behavior?

  They explain atomic properties
• The main periodic trends are influenced by effective nuclear charge and shielding.
• The effective nuclear charge (Zeff) is calculated as the nuclear charge minus the shielding constant.
• Shielding weakens the nuclear pull, resulting in a larger atomic radius down a group.


  True
• Ionization energy increases across a period because effective nuclear charge increases.


  True
• Electron affinity becomes more negative across a period due to increasing effective nuclear charge.


  True
• Electronegativity helps predict bond polarity and chemical reactivity.


  True
• Periodic trends are systematic changes in element properties influenced by effective nuclear charge and the shielding effect.
• Across a period, atomic radius decreases, while down a group, it increases.
• What happens to electronegativity across a period?

  Increases
• Why does effective nuclear charge increase across a period?

  Added protons
• What is the formula for calculating effective nuclear charge (Zeff)?

  $Z_{\text{eff}} =$$Z - S$
• What effect does a higher effective nuclear charge (Zeff) have on atomic size?

  Decreases atomic size
• What is the definition of ionization energy?

  Energy to remove electron
• What is electron affinity?

  Energy change adding electron
• What is electronegativity?

  Ability to attract electrons