4.1.1 Physical Properties

• Where are alkaline earth metals located in the periodic table?

  Group 2
• Alkaline earth metals are generally less reactive than alkali metals but more reactive than most other metals
• Alkaline earth metals form stable cations with a +2 oxidation state.
• What is the general electronic configuration of alkaline earth metals?

  [noble gas] ns^2
• The electronic configuration of Magnesium (Mg) is [Ne] 3s^2
• The electronic configuration of Calcium (Ca) is [Ar] 4s^2.
• Match the alkaline earth metal with its electronic configuration:

  Magnesium ↔️ [Ne] 3s^2

  Calcium ↔️ [Ar] 4s^2

  Strontium ↔️ [Kr] 5s^2

  Barium ↔️ [Xe] 6s^2
• What oxidation state do alkaline earth metals achieve when they lose two electrons?

  +2
• Alkaline earth metals achieve a stable noble gas configuration by losing two electrons
• Alkaline earth metals lose two electrons to achieve a stable noble gas configuration, resulting in a +2
• What is the general electronic configuration of alkaline earth metals in Group 2?

  [Noble gas] ns^2
• Match the alkaline earth metal with its electronic configuration:

  Magnesium (Mg) ↔️ [Ne] 3s^2

  Calcium (Ca) ↔️ [Ar] 4s^2

  Strontium (Sr) ↔️ [Kr] 5s^2

  Barium (Ba) ↔️ [Xe] 6s^2
• The atomic radius of alkaline earth metals increases down the group due to greater electron shielding
• Ionization energy of alkaline earth metals decreases as one descends Group 2.
• Order the following alkaline earth metals based on increasing atomic radius:

  1️⃣ Magnesium (Mg)

  2️⃣ Calcium (Ca)

  3️⃣ Strontium (Sr)

  4️⃣ Barium (Ba)
• Why does the melting point of alkaline earth metals decrease down the group?

  Weakening metallic bonding
• The density of alkaline earth metals increases down the group because mass increases faster than volume
• The melting points and boiling points of alkaline earth metals decrease down the group due to larger atomic radii and lower effective nuclear charges.
• Where are alkaline earth metals located in the periodic table?

  Group 2
• When alkaline earth metals form ions, they become +2 ions, which are smaller than their neutral atoms.
• What is the atomic radius of calcium (Ca) in picometers?

  197 pm
• Ionization energy decreases down Group 2 due to increasing atomic radius
• Increased electron shielding makes it easier to remove outer electrons from alkaline earth metals as one descends the group.
• What is the oxidation state of alkaline earth metals in their compounds?

  +2
• For alkaline earth metals, the atomic radii increase down the group due to the addition of electron shells
• Atomic radii increase down Group 2 due to increased electron shielding against the nuclear charge.
• When alkaline earth metals form ions, they become +2
• The ionic radii of alkaline earth metals are smaller than their atomic radii.
• Match the element with its atomic radius:

  Magnesium (Mg) ↔️ 160 pm

  Calcium (Ca) ↔️ 197 pm

  Strontium (Sr) ↔️ 215 pm

  Barium (Ba) ↔️ 222 pm
• Order the alkaline earth metals from smallest to largest atomic radius:

  1️⃣ Magnesium (Mg)

  2️⃣ Calcium (Ca)

  3️⃣ Strontium (Sr)

  4️⃣ Barium (Ba)
• The first ionization energy of alkaline earth metals decreases as you move down the group
• Ionization energy is the energy required to remove an electron from an atom in the gaseous phase.
• Why does the ionization energy decrease down Group 2?

  Increasing atomic radius
• Increased electron shielding reduces the nuclear attraction, making it easier to remove electrons.
• Match the element with its first ionization energy:

  Beryllium (Be) ↔️ 899 kJ/mol

  Magnesium (Mg) ↔️ 738 kJ/mol

  Calcium (Ca) ↔️ 590 kJ/mol

  Strontium (Sr) ↔️ 549 kJ/mol
• Order the alkaline earth metals from highest to lowest first ionization energy:

  1️⃣ Beryllium (Be)

  2️⃣ Magnesium (Mg)

  3️⃣ Calcium (Ca)

  4️⃣ Strontium (Sr)

  5️⃣ Barium (Ba)
• The density of alkaline earth metals increases down Group 2.
• Why does density increase down Group 2?

  Atomic mass increases more
• The electrical conductivity of alkaline earth metals decreases down the group due to increasing atomic radius
• The strength of metallic bonding in alkaline earth metals decreases down Group 2.