chem chap 7

• How did Mendeleev organize his periodic table?

  By increasing mass number
• What was a key feature of Mendeleev's periodic table?

  He left gaps for unknown elements
• How is the periodic table organized now?

  By increasing atomic number
• What is periodicity in the context of the periodic table?

  The repeating trend in properties of elements
• What does the period number indicate?

  The number of electron shells
• What does the group number tell you?

  The number of electrons in the outer shell
• What does each period start with?

  An electron in a new highest energy shell
• Which sub shell fills first in a new period?

  The s sub shell
• Where is the s block located in the periodic table?

  Groups 1 and 2 and helium
• Where is the p block located in the periodic table?

  Groups 13-18
• Where is the d block located in the periodic table?

  Groups 3-12
• Where is the f block located in the periodic table?

  Lanthanides and actinides at the bottom
• What groups are the transition metals found in?

  Groups 3-12
• What does ionisation energy measure?

  How easily an atom loses electrons
• What is the first ionisation energy?

  Energy needed to remove 1 electron from 1 mole
• What are the factors affecting ionisation energy?

  • Atomic radius
  • Nuclear charge
  • Electron shielding
• How does atomic radius affect ionisation energy?

  As atomic radius increases, ionisation energy decreases
• Why does a greater atomic radius lead to lower ionisation energy?

  Less nuclear attraction due to distance
• What happens to ionisation energy as nuclear charge increases?

  Ionisation energy increases
• How does nuclear charge affect ionisation energy?

  More protons increase attraction to outer electrons
• What happens to ionisation energy as electron shielding increases?

  Ionisation energy decreases
• How does electron shielding affect ionisation energy?

  Inner electrons repel outer electrons, reducing attraction
• What is the second ionisation energy?

  Energy needed to remove 1 electron from 1 mole of 1+ ions
• Is the second ionisation energy higher or lower than the first?

  Higher
• Why is the second ionisation energy higher than the first?

  Increased nuclear attraction after first electron loss
• What do successive ionisation energies provide evidence of?

  The existence of shells and sub-shells
• How do successive ionisation energies provide evidence of shells?

  Significant increases occur when losing electrons from lower shells
• What do elements near the divide of the metal/non-metal section show?

  In-between properties
• How can you determine an element's identity from successive ionisation energies?

  Identify significant jumps in ionisation energies
• What are elements near the metal/non-metal divide called?

  Semi-metals and metalloids
• What happens to ionisation energy when moving along a period?

  Ionisation energy increases
• What are the properties of metals?

  • Good conductor of electricity
  • Good conductor of heat
  • Malleable
  • Lustrous (shiny)
  • Hard
  • Ductile
  • Strong
  • High density
  • Solid at room temperature
• Why does ionisation energy decrease as you move down a group?

  Atomic radius increases and shielding increases
• What are the properties of metals due to?

  Metallic bonding
• What happens to first ionisation energy as you move across a period?

  First ionisation energy increases
• What is metallic bonding?

  • Electrostatic attraction between delocalised electrons and positive metal ions
  • Forms a giant metallic lattice
  • Strong forces requiring high energy to overcome
• Why does first ionisation energy increase as you move across a period?

  Nuclear charge increases while shielding remains similar
• Why do metals have high melting and boiling points?

  Strong electrostatic attraction requires much energy
• Why is it more stable to have full or singly full sub-shells?

  Equal repulsion among electrons in full shells
• In what states do metals conduct electricity?

  Solid and liquid states