- The vertical columns in the periodic table of the elements are known as groups.
- The second vertical column from the left in the periodic table is referred to as Group 2.
Alternative names for Group 2 are:
(a) alkali earth metals (still commonly used)
(b) alkaline earth metals, or alkaline-earth metals (1) (still commonly used)
(c) group IIA (this numbering is no longer used)
- The name and symbol for the elements in Group 2 are given below:
Group 2 Elements
name symbol beryllium Be magnesium Mg calcium Ca strontium Sr barium Ba radium Ra
- Except for beryllium(2), the Group 2 elements are typical metals:(a) relatively soft, but harder than group 1 metals, shiny solids at room temperature and pressure that are good conductors of heat and electricity(b) Moderately-high melting point.(c) have 2 valence electrons (2 electrons in the highest energy level)(d) are very reactive(e) form cations with a charge of +2 (M2+) when they combine with non-metals in an ionic compound(f) form white ionic compounds (3)
- Going down group 2 from top to bottom the elements display the following general trends:
(a) Atomic radius increases.
(b) First ionization energy decreases.
(c) Second ionization energy decreases.
Second ionization energy is about double the first ionization energy for each element.
(d) Third ionization energy decreases.
Third ionization energy is much greater, about 4 times greater, than the second ionization energy for each element.
(e) Electronegativities decrease as successive energy levels (electron shells) are filled resulting in the positive nucleus exerting less of a force of attraction on electrons.
(f) Chemical reactivity increases
(g) Densities generally increase.(4)
- Summary of trends in Group 2 elements:
Trends: Decreasing Group 2 Elements Trends: Increasing First Ionisation Energy Second Ionisation Energy Third Ionisation Energy Electro-
name symbol atomic number atomic radius Reactivity largest largest largest highest beryllium Be lowest smallest less reactive ↑ ↑ ↑ ↑ magnesium Mg ↓ ↓ ↓ ↑ ↑ ↑ ↑ calcium Ca ↓ ↓ ↓ ↑ ↑ ↑ ↑ strontium Sr ↓ ↓ ↓ smallest smallest smallest lowest barium Ba highest largest most reactive