Crystals are characterized by particular patterns that repeat in how many dimensions? a. three dimensions b. one dimension only c. two dimensions only

A. three dimensions

Explanation:

Crystal lattice have a three dimensional array of repeating units. For example, in the NaCl crystal the repeating units are the Na⁺ and Cl⁻ ions. The Na⁺ and Cl⁻ ions are arranged alternately along the x, y and z axis. The smallest repeating unit of a cell is called unit cell. Crystal lattice have a definite geometry which is because of this rigid array of unit cells.

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-