Why do the elements in the group 1 and 2 react with group 17?

Answer 1

Elements in group 1 have 1 electron in their outer shell. Group 7 electrons have 7 electrons in their outer shell. This means that the group 1 element needs to give its electron to the group 7 element so that they both have full outer shells, making them stable. By a school boy in yr. 10

Answer 2

The groups in The Periodic Table of Elements categorize elements according to the number of electrons in the outer shell. Atoms wish to obtain a complete outer shell eg. 2 electrons in the first shell, 8 in the rest. Group 1 elements have 1 electron in the outer shell (valence electrons). To obtain a complete outer shell, the atoms give their electron away. Group 7 elements have 7 valence electrons and require 1 more electron to obtain a complete outer shell. They can receive the electron given from the group 1 elements. This creates a charge in the atoms. Group 1 elements have more protons than electrons and so have a positive charge. Group 7 elements have less protons than electrons and so have a negative charge. The negatively charged atoms (anions) and the positively charged atoms (cations) are attracted to each other.

Hydrogen- a group 1 element, reacts really well with fluorine- a group 7 element. It forms an ionic bond when the anions and cations form a 3D fixed lattice.

Answer 3

The group 1 and 2 elements have much lower electronegativity value than group 17 elements and therefore lose electrons to the group 17 elements. The group 17 elements require only one more electron to have a full valence shell and thereby acquire the stable electron configuration of the next higher atomic number noble gas. The group 1 and 2 elements achieve a stable electron configuration when they lose all their outermost (valence) electrons and thereby acquire the electron configuration of the next lower atomic number noble gas. One group 1 element will combine with one group 17 element and one group 2 element will combine with two group 17 elements. Examples include NaF, and MgCl2.

Answer 4

Group 1 atoms only need to lose 1 electron in order to achieve a noble gas configuration, and group 7 atoms only need to gain 1 electron to achieve a noble gas configuration.

Answer 5

group 1 elements have to 'lose' one electron to fill their outermost shell of electrons

group 7 elements have to 'gain' one electron to complete their outermost shell of electrons