How many valence electrons are present in this atom?

ionization energy

i 496

ii 4562

iii 6912

iv 9544

v 13353

one
two
three
four

Which diagram shows the correct way to represent an ionic compound of magnesium oxide?

The melting point of sulfur is 115 °c and its boiling point is 445 °c. what state would sulfur be in at 200 °c?

One way in which the useful metal copper is produced is by dissolving the mineral azurite, which contains copper(ii) carbonate, in concentrated sulfuric acid. the sulfuric acid reacts with the copper(ii) carbonate to produce a blue solution of copper(ii) sulfate. scrap iron is then added to this solution, and pure copper metal precipitates out because of the following chemical reaction: (s) (aq) (s) (aq) suppose an industrial quality-control chemist analyzes a sample from a copper processing plant in the following way. he adds powdered iron to a copper(ii) sulfate sample from the plant until no more copper will precipitate. he then washes, dries, and weighs the precipitate, and finds that it has a mass of .