The most common reaction pattern for transition elements (d block) is losing two electrons. What does this fact suggest about how these elements lose electrons? A few sample electron configurations may be useful to reference in your answer.

Explanation:

Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.

The electrons are filled according to Afbau's rule in order of increasing energies and thus the electronic configuration  for bromine with atomic number of 35 and thus containing 35 electrons is:

The nearest noble gas is Argon with 18 electrons and thus electronic configuration  for bromine in terms of noble gas is:

OK so, "question" 1 and 2 are an example question of the relationship between mass, volume, and density and they work you through the problem and answer it for you so... you should probably probably just read it.