1 mole contains = 6.02x10^23 atoms. 0.31mole contains = 0.31x6.02x10^23 = 1.8662x10^23.
Answer:
d
. Sc2O5
Explanation:
Hello,
In this case, when forming oxides from a metal and oxygen, for us to find out each element's subscript, we must exchange them as shown below, considering +5 for scandium:

For that reason, the answer is d
. Sc2O5
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Answer: The mass in
atoms of zinc is 0.405 g.
Explanation:
Given: Atoms of zinc = 
It is known that 1 mole of every substance contains
atoms. So, the number of moles in given number of atoms is as follows.

As moles is the mass of a substance divided by its molar mass. So, mass of zinc (molar mass = 65.39 g/mol) is calculated as follows.

Thus, we can conclude that the mass in
atoms of zinc is 0.405 g.
Fluorine (F) will have properties similar to Bromine (Br) because it belongs to the same group as Bromine.
Potassium oxide: K₂O.
There's no need for prefixes since K₂O is an ionic compound.
<h3>Explanation</h3>
Find the two elements on a periodic table:
- Potassium- K- on the left end of period four.
- Oxygen- O- near the right end of periodic two.
Elements on the bottom-left corner of the periodic table are metals. Those on the top-right corner are nonmetals.
- Potassium is a metal,
- Oxygen is a nonmetal.
A metal and a nonmetal combine to form an ionic compound. Potassium oxide is likely to be an ionic compound. It contains two types of ions:
- Potassium ions: Potassium is group 1 of the periodic table. It is an alkaline metal. Like other alkaline metals such as sodium Na, potassium K tends to lose one electron and form ions of charge +1 in compounds. The ion would be K⁺.
- Oxide ions from oxygen: Oxygen is the second most electronegative element on the periodic table. It tends to gain two electrons and form the oxide ion
when it combines with metals.
The two types of ions carry opposite charges. They shall pair up at a certain ratio such that they balance the charge on each other. The charge on each
ion is twice that on a
ion. Each
would pair up with two
. Hence the subscript in the formula:
.
There are two classes of compounds:
- Covalent compounds, which need prefixes, and
- Ionic compounds, which need no prefix.
Prefixes are needed only in covalent compounds. For instance in the covalent compound carbon dioxide
, the prefix di- indicates that there are two oxygen atoms in the formula
. However, there's no need for prefix in ionic compounds such as
.