Question

question 1
match the ion to the noble gas element it is isoelectronic to.
carbide
phosphide
potassium ion
strontium ion
beryllium ion

Explanation:

Step1: Determine electrons in carbide ($C^{4 -}$)

Carbon has 6 electrons. $C^{4 -}$ has 6 + 4=10 electrons, which is isoelectronic with Ne.

Step2: Determine electrons in phosphide ($P^{3 -}$)

Phosphorus has 15 electrons. $P^{3 -}$ has 15+ 3 = 18 electrons, which is isoelectronic with Ar.

Step3: Determine electrons in potassium ion ($K^{+}$)

Potassium has 19 electrons. $K^{+}$ has 19 - 1=18 electrons, which is isoelectronic with Ar.

Step4: Determine electrons in strontium ion ($Sr^{2+}$)

Strontium has 38 electrons. $Sr^{2+}$ has 38 - 2 = 36 electrons, which is isoelectronic with Kr.

Step5: Determine electrons in beryllium ion ($Be^{2+}$)

Beryllium has 4 electrons. $Be^{2+}$ has 4 - 2=2 electrons, which is isoelectronic with He.

Answer:

carbide: Ne
phosphide: Ar
potassium ion: Ar
strontium ion: Kr
beryllium ion: He