I will mark brainliest if you are correct Which statement about pure substances and elements is correct?

a
All pure substances are elements.
b
All elements are pure substances.
c
Pure substances cannot be elements.
d
Elements cannot be pure substances.

An atom of sodium-23 (atomic number = 11) has a positive charge of +1. give this information, how many electrons does it have? how many proteins and neutrons does this atom have

How have the greenhouse gasses increased from the year 2000 to 2018

Give the set of reactants (including an alkyl halide and a nucleophile) that could be used to synthesize the following ether: draw the molecules on the canvas by choosing buttons from the tools (for bonds and charges), atoms, and templates toolbars, including charges where needed. ch3ch2och2ch2chch3 | ch3