Which is the electron configuration for bromine?

A+b→2c when the reaction begins, the researcher records that the rate of reaction is such that 1 mole of a is consumed per minute. after making changes to the reaction, the researcher notes that 2 moles of a are consumed per minute. what change could the researcher have made to effect this change?

Name the element in group 17, period 2. (periodic table)

What happens to isotopes that are unstable?