8 because atomic number is the same as number of protons, protons and electrons have the same amount so that the element is neither positive nor negative.
Answer: 1. 0.045moles
2. 2.10 grams
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 
of particles.
To calculate the moles, we use the equation:
1. 
2. Mass of 
Kinetic Molecular Theory states that gas particles are in constant motion and exhibit perfectly elastic collisions.
Answer is (2) - hydrogen carbonate
<em>Explanation:</em>
NaHCO₃ is an ionic compound which is made from Na⁺ and HCO₃⁻ ions. The decomposition is
NaHCO₃ → Na⁺ + HCO₃⁻
Among the resulted ions, Na⁺ is a monatomic ion while HCO₃⁻ is a polyatomic ion.
<em>Polyatomic ions mean ions which are made of two or more different atoms.</em>
HCO₃⁻ is made from 3 atoms as H, C and O. The name of HCO₃⁻ ion is bicarbonate or hydrogen carbonate.
Answer
D
Explanation
<em>the</em><em> </em><em>answer</em><em> </em><em>is</em><em> </em><em>D</em>
