Calcium fluoride.
Ca is metal, F is non-metal, so they form ionic bond.
Ca as metal can form only positive ion. Ca in the second group, so the charge of Ca ion is 2+. Ca²⁺
F is in the 17th group, so it has 7 electrons on the last level. It is non-metal, non-metal, so it has negative charge -(8-7)=-1. "8" because on the last level cannot be more than 8 electrons. F-ion is F¹⁻.
Ca²⁺ F¹⁻
Number of positive charges should be equal to number of negative charges,
Formula of calcium fluoride
CaF2.
2 atoms Fluorine bond with Calcium.
<u>Answer:</u> The fugacity coefficient of a gaseous species is 1.25
<u>Explanation:</u>
Fugacity coefficient is defined as the ratio of fugacity and the partial pressure of the gas. It is expressed as 
Mathematically,
Partial pressure of the gas is expressed as:
Putting this expression is above equation, we get:
where,
= fugacity coefficient of the gas
= fugacity of the gas = 25 psia
= mole fraction of the gas = 0.4
P = total pressure = 50 psia
Putting values in above equation, we get:
Hence, the fugacity coefficient of a gaseous species is 1.25
That is a steep slope for sure, no doubt about it. Hope this helps!
<h3>
Answer:</h3>
D. Allotrope
<h3>
Explanation:</h3>
What is allotropy?
- Allotropy refers to the existence of an element in more than one physical forms.
- Allotropes are therefore different forms of an element with different physical properties or chemical arrangements.
What are some examples of allotropes?
- Examples of elements that exhibit allotropy include, sulfur and carbon.
- Allotropes of carbon are diamond and graphite.
- Allotropes of sulfur are monoclinic sulfur and rhombic sulfur.
