Question

List the symbols for helium, silicon, phosphorus, and magnesium in order of decreasing electronegativity.

A) He, Si, P, Mg
B) Mg, P, Si, He
C) He, Si, Mg, P
D) Si, Mg, P, He

Answer 1

The symbols for helium, silicon, phosphorus, and magnesium in order of decreasing electronegativity are phosphorus (P), silicon (Si), magnesium (Mg), and helium (He), which corresponds to Option C: P, Si, Mg, He.

Step-by-step explanation:

To list the symbols for helium, silicon, phosphorus, and magnesium in order of decreasing electronegativity, we need to consider the trends of electronegativity on the periodic table. Electronegativity generally increases as you move from left to right across a period and from bottom to top along a group. Based on these trends and excluding the noble gases like helium which generally do not form compounds and hence electronegativity is not often defined, phosphorus (P) is more electronegative than silicon (Si), which in turn is more electronegative than magnesium (Mg). However, since we are including helium in the list, which is a noble gas with very low reactivity, it would theoretically be placed at the end of the list. The correct order of decreasing electronegativity, considering we define a value for helium, would be phosphorus (P), silicon (Si), magnesium (Mg), and then helium (He).

Therefore, the correct sequence for the symbols of these elements in order of decreasing electronegativity, including helium, is:

1. Phosphorus (P)
2. Silicon (Si)
3. Magnesium (Mg)
4. Helium (He)

So, the correct answer would be Option C: P, Si, Mg, He.