Question

what is the lewis symbol for k+?

Explanation:

Step1: Determine K atom's electron configuration

Potassium (K) has atomic number 19, so its electron - configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}$.

Step2: Consider $K^{+}$ formation

$K^{+}$ is formed when K loses one electron. The outermost 4s electron is lost.

Step3: Write the Lewis symbol

After losing one electron, $K^{+}$ has the same electron - configuration as argon (Ar), which has 18 electrons. So the Lewis symbol for $K^{+}$ is represented by the noble - gas core of argon, written as $[\text{Ar}]$.

Answer:

$[\text{Ar}]$