We only know they exist because of patterns in the periodic table. The interesting trend in melting and boiling points of Group 7 elements allows us to make predictions about their physical ...

Chemists use symbols and formulae to represent elements and compounds. Word equations and balanced chemical equations represent the changes that happen in chemical reactions. Mixtures - AQA There ...

Chlorine is a halogen in group VII A of the periodic table with atomic number 17, an atomic weight of 35.45, and a density of 1.56 Mg/m 3. In the solid state it forms a tretragonal crystal with a ...

Argon is an inert gas in group VIII A of the periodic table with atomic number 18, an atomic weight of 39.948, and a density of 1.40 Mg/m 3. In the solid state it forms an fcc crystal with a melting ...