An ionic<span> crystal consists of </span>ions<span> bound together by electrostatic attraction. The arrangement of </span>ions<span> in a regular, geometric structure is called a crystal lattice. Examples of such </span>crystals<span> are the alkali halides, which include: potassium fluoride </span>
Through hypothesis and experiments
<span>The </span>elements are arranged<span> in order of increasing atomic number. Vertical columns(called groups) contain </span>elements with similar properties. Horizontal rows called periods elements with<span> the same number of atomic orbitals(That's why Hydrogen and Helium are separated from the rest of the table).
Hope this helps:)</span>
Compare HCl, NaOH, and NaCl: HCl is a stronger acid than water. NaCl is a weaker base than NaOH. Strong acids react with strong bases to form weaker acids and bases. ... Compare NaOH, NH3, and H2O, and NH4Cl: NaOH is a stronger base than NH3.
In math it’s just horizontal in science it’s periods