Answer:
A is Mg^2+
B is K^+
C is Se^2-
D is Cl^-
Ca^2+ lies between Mg^2+ and K^+
S^2- lies between K^+ and Se^2-
Explanation:
I have attached an image of the four spheres.
Remember that, cations are smaller in size than the corresponding atom atom because the formation of a cation often involves the removal of an entire shell. Anions are larger in size than the corresponding atom because an electron is added thereby expanding the electron cloud and size of the anion.
From left to right let us designate the spheres as ABCD.
A is Mg^2+
B is K^+
C is Se^2-
D is Cl^-
Ca^2+ lies between Mg^2+ and K^+
S^2- lies between K^+ and Se^2-
Answer:
1.48×10²⁴ Cu atoms
Explanation:
For this question you need to use Avogadro's number 6.022×10²³atoms.
2.45 moles of Cu ×= 1.47539×10²⁴ atoms.
The moles cancel out so you are left with atoms.
Since there are 3 significant figures in the question there should be 3 significant figures in your answer, which is 1.48×10²⁴ Cu atoms.