calcium vs magnesium vs potassium

calcium (chemical element) | magnesium (chemical element) | potassium (chemical element)

Periodic table location

Images

| calcium | magnesium | potassium atomic symbol | Ca | Mg | K atomic number | 20 | 12 | 19 short electronic configuration | [Ar]4s^2 | [Ne]3s^2 | [Ar]4s^1 Aufbau diagram | 4s | 3s | 4s block | s | s | s group | 2 | 2 | 1 period | 4 | 3 | 4 atomic mass | 40.078 u | 24.305 u | 39.0983 u half-life | (stable) | (stable) | (stable)

| calcium | magnesium | potassium phase at STP | solid | solid | solid melting point | 842 °C | 650 °C | 63.38 °C boiling point | 1484 °C | 1090 °C | 759 °C critical temperature | | (unknown) | 2223 K critical pressure | | (unknown) | 16 MPa molar heat of fusion | 8.54 kJ/mol | 8.7 kJ/mol | 2.33 kJ/mol molar heat of vaporization | 155 kJ/mol | 128 kJ/mol | 76.9 kJ/mol specific heat at STP | 631 J/(kg K) | 1020 J/(kg K) | 757 J/(kg K) (properties at standard conditions)

| calcium | magnesium | potassium density | 1.55 g/cm^3 | 1.738 g/cm^3 | 0.856 g/cm^3 liquid density | 1.378 g/cm^3 | 1.584 g/cm^3 | 0.828 g/cm^3 molar volume | 25.86 cm^3/mol | 13.98 cm^3/mol | 45.7 cm^3/mol Mohs hardness | 1.75 (between gypsum and talc) | 2.5 (between gypsum and calcite) | 0.4 (between talc and gypsum) Brinell hardness | 167 MPa | 260 MPa | 0.363 MPa bulk modulus | 17 GPa | 45 GPa | 3.1 GPa shear modulus | 7.4 GPa | 17 GPa | 1.3 GPa Young's modulus | 20 GPa | 45 GPa | Poisson ratio | 0.31 | 0.29 | sound speed | 3810 m/s | 4602 m/s | 2000 m/s thermal expansion | 2.23×10^-5 K^(-1) | 2.5×10^-5 K^(-1) | thermal conductivity | 200 W/(m K) | 160 W/(m K) | 100 W/(m K) (properties at standard conditions)

| calcium | magnesium | potassium electrical type | conductor | conductor | conductor resistivity | 3.4×10^-8 Ω m (ohm meters) | 4.4×10^-8 Ω m (ohm meters) | 7×10^-8 Ω m (ohm meters) electrical conductivity | 2.9×10^7 S/m (siemens per meter) | 2.3×10^7 S/m (siemens per meter) | 1.4×10^7 S/m (siemens per meter) magnetic type | paramagnetic | paramagnetic | paramagnetic volume magnetic susceptibility | 2.139×10^-5 | 1.2×10^-5 | 5.74×10^-6 mass magnetic susceptibility | 1.38×10^-8 m^3/kg (cubic meters per kilogram) | 6.9×10^-9 m^3/kg (cubic meters per kilogram) | 6.7×10^-9 m^3/kg (cubic meters per kilogram) molar magnetic susceptibility | 5.531×10^-10 m^3/mol (cubic meters per mole) | 1.68×10^-10 m^3/mol (cubic meters per mole) | 2.62×10^-10 m^3/mol (cubic meters per mole) work function | 2.87 eV (Polycrystalline) | 3.66 eV (Polycrystalline) | 2.29 eV (Polycrystalline) threshold frequency | 6.94×10^14 Hz (hertz) | 8.85×10^14 Hz (hertz) | 5.537×10^14 Hz (hertz) color | (silver) | (silver) | (silver)

| calcium | magnesium | potassium valence | 2 | 2 | 1 electronegativity | 1 | 1.31 | 0.82 electron affinity | 2.37 kJ/mol (kilojoules per mole) | 0 kJ/mol (kilojoules per mole) | 48.4 kJ/mol (kilojoules per mole) first ionization energy | 589.8 kJ/mol (kilojoules per mole) | 737.7 kJ/mol (kilojoules per mole) | 418.8 kJ/mol (kilojoules per mole) ionization energies | 589.8 kJ/mol | 1145.4 kJ/mol | 4912.4 kJ/mol | 6491 kJ/mol | 8153 kJ/mol | 10496 kJ/mol | 12270 kJ/mol | 14206 kJ/mol | 18191 kJ/mol | 20385 kJ/mol | 57110 kJ/mol | 737.7 kJ/mol | 1450.7 kJ/mol | 7732.7 kJ/mol | 10542.5 kJ/mol | 13630 kJ/mol | 18020 kJ/mol | 21711 kJ/mol | 25661 kJ/mol | 31653 kJ/mol | 35458 kJ/mol | 418.8 kJ/mol | 3052 kJ/mol | 4420 kJ/mol | 5877 kJ/mol | 7975 kJ/mol | 9590 kJ/mol | 11343 kJ/mol | 14944 kJ/mol | 16963.7 kJ/mol | 48610 kJ/mol

Reactivity

| calcium | magnesium | potassium term symbol | ^1S_0 | ^1S_0 | ^2S_(1/2) atomic radius | 180 pm | 150 pm | 220 pm covalent radius | 176 pm | 141 pm | 203 pm van der Waals radius | | 173 pm | 275 pm (electronic ground state properties)

| calcium | magnesium | potassium universe abundance | 0.007 mass% | 0.06 mass% | 3×10^-4 mass% solar abundance | 0.007 mass% | 0.07 mass% | 4×10^-4 mass% meteorite abundance | 1.1 mass% | 12 mass% | 0.07 mass% crust abundance | 5 mass% | 2.9 mass% | 1.5 mass% ocean abundance | 4.2×10^-4 mass% | 0.13 mass% | 0.042 mass% human abundance | 1.4 mass% | 0.027 mass% | 0.2 mass% universe molar abundance | 2×10^-4 mol% | 0.003 mol% | 1×10^-5 mol% solar molar abundance | 2×10^-4 mol% | 0.003 mol% | 9.9×10^-6 mol% meteorite molar abundance | 0.52 mol% | 10 mol% | 0.037 mol% ocean molar abundance | 6.5×10^-5 mol% | 0.034 mol% | 0.0066 mol% crust molar abundance | 2.6 mol% | 2.5 mol% | 0.78 mol% human molar abundance | 0.22 mol% | 0.007 mol% | 0.032 mol%