Answer
(a) A dark-red liquid - Bromine (Br2)
(b) A colorless gas that burns in oxygen gas - Hydrogen (H2)
(c) A reactive metal that attacks water - Calcium (Ca)
(d) A shiny metal that is used in jewelry - Gold (Au)
(e) An inert gas - Argon (Ar)
Work Step by Step
(a) A dark-red liquid - Bromine (Br2).
Bromine is a red-colored liquid at room temperature.
(b) A colorless gas that burns in oxygen gas - Hydrogen (H2).
Hydrogen is a colorless highly inflammable gas.
(c) A reactive metal that attacks water - Calcium (Ca).
Calcium is a reactive alkaline earth metal which reacts with water and forms calcium hydroxide.
(d) A shiny metal that is used in jewelry - Gold (Au).
Gold is one of the highly malleable and ductile metals with a shiny appearance, so it is used in jewelry.
(e) An inert gas - Argon (Ar).
Argon is an inert gas with an atomic number of 18. It has a complete octet configuration. Its electronic configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}$
