Group 1:
Alkali metals
The element in the first column of the periodic is called the alkali metals, they all have one valence electron, that means each of them has only one electron in the outer shell.
characteristics and properties
Alkali metals are very soft, they have low melting points and boiling points compared to most of the other metals of the periodic table. Both melting points and boiling points decrease and softer as you go down the group. However, although the alkali metals have low densities compared to most of other metals, the densities increase as you go down the group.
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The reactivity of the alkali metals are very high, it is because they have only one valence electron to get rid of. As you go down the group the reactivity increase, it is because the bigger the atom is, the further the valence electron is from the nucleus and since it is far away from the nucleus, the force which pulls the valence electron in will be weaker, therefore, it is easier for the valence electron to escape the atom.
trends: (As you go down the group)
- Melting point and boiling point decreases
- Density increases
- Reactivity increases
Bonding
Since all of the atoms of group 1 have one valence electron, when bonding, they usually gives away one electron so they can have a positive +1 charge and gain a full shell of valence electrons which let them become a positive charged ion
For example, look at the diagram in the right side, it is a bonding diagram of sodium and chloride. You can see that sodium gives one electron to chlorine so they both can have full shell of valence electrons, and sodium becomes an ion with a +1 charge.
sources:
-Physical properties of the alkali metals. (n.d.). Retrieved December 10, 2016, from http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_pre_2011/periodic_table/group1rev2.shtml
-Electron arrangement and chemical properties of Group 1 - Higher. Retrieved December 10, 2016, from http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_pre_2011/periodic_table/electronsrev4.shtml