Question

some physical properties of elements in a group of the periodic table are described below.
poor conductor of electricity
poor conductor of thermal energy
atoms contain seven valence electrons
brittle in the solid state
low melting points and boiling points
the elements described above belong to which group?
noble gases
alkaline earth metals
halogens
alkali metals

Explanation:

• Noble gases: Have full valence shells (8 electrons except helium with 2), not 7.
• Alkaline earth metals: Have 2 valence electrons, are good conductors (electricity and heat), and are not brittle.
• Halogens: Have 7 valence electrons. They are non - metals (poor conductors of electricity and heat), brittle in solid state, and have low melting and boiling points.
• Alkali metals: Have 1 valence electron, are good conductors, and are not brittle.

Answer:

Halogens