Answer:
D
Explanation:
Because the atomic number is 8, we can see that it is indeed an isotope of oxygen. If the mass number is 18, this means that the protons and neutrons added together = 18, so there are 10 neutrons. It does not have an atomic mass of 15.9994 like the element on the periodic table, however, as this is a confirmed isotope and not an average.
Be and B: Be is 1s2 2s2 and B is 1s2 2s2 2p1
Be has full 2 orbitals and so does B but B only has 1 electron in p so it is really unstable and easy to react. So there is a dip in ionization energies. The other questions are similar to this so if you need, feel free to ask me
Sodium hydrogen carbonate has:

The + from Na+ and + from H+ makes 2+, and therefore the 2- from CO3 evens the charges to neutral.
Not to be confused with Sodium Carbonate, (Na2CO3), which lack an H, Sodium Hydrogen Carbonate is sometimes shortened to just Sodium Bicarbonate. It is used in the kitchen (cooking) as "baking soda."
Formula: NaHCO3

Volume of 20 g of hydrogen at normal temperature and pressure (NTP) = 240.55 ml.

Answer:
a: increasing the positive charge of the positively charged object and increasing the negative charge of the negatively charged object
Explanation: