Answer:

Explanation:
Alkaline earth metals are in group 2. The number of valence electrons of elements in group 2 is 2.
Answer: the concentration of H in the stomach acid is greater than that of the lemon juice
Explanation:Please see attachment for explanation
Answer:
In my opinion, I think its 2
Explanation:
Group 4A
The elements in group 4 show the most diverse set of properties.
B) 40%
The balanced equation indicates that for every 3 moles of H2 used, 2 moles of NH3 will be produced. So the reaction if it had 100% yield would produce (2.00 / 3) * 2 = 1.333333333 moles of NH3. But only 0.54 moles were produced. So the percent yield is 0.54 / 1.3333 = 0.405 = 40.5%. This is a close enough match to option "b" to be considered correct.