Answer:
Explanation:
Atom X,
Neutron num = 4, Mass num = 7
Therefore, proton number = Mass num - Neutron num
= 7 - 4
= 3
Atom Y,
Neutron num = 5, Mass num = 9
Therefore, proton number = Mass num - Neutron num
= 9 - 5
= 4
1) False. Atom X belongs to group 3 while atom Y belongs to group 4
2) False. Atom X is in a column on the left of Atom Y
3) True. Atom X and atom Y belong to the same period two on the periodic table
4) Fasle. Atom X and Y are not isotopes because they do not have the same atomic number.
Isotopy is a phenomenon whereby atom of same element have same atomic number but different mass number
B . microscope
this is the answer .
Answer: Moles of hydrogen required are 4.57 moles to make 146.6 grams of methane, 
.
Explanation:
Given: Mass of methane = 146.6 g
As moles is the mass of a substance divided by its molar mass. So, moles of methane (molar mass = 16.04 g/mol) are calculated as follows.
The given reaction equation is as follows.
This shows that 2 moles of hydrogen gives 1 mole of methane. Hence, moles of hydrogen required to form 9.14 moles of methane is as follows.
Thus, we can conclude that moles of hydrogen required are 4.57 moles to make 146.6 grams of methane, .
Answer:
The answer to your question is D. 25 grams.
The answer is B. This is because Sodium has 1 valence electron and Fluorine has 7 valence electrons. All elements want 8 valence electrons so they may be stale, like the noble gases are. Hope this helps.
