Question
(ii) Potassium ions, K^+, are formed from potassium atoms. Describe how a potassium atom forms a potassium ion. (2)
Answer
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Ulysses
Master · Tutor for 5 years
Answer
A potassium atom forms a potassium ion (
) by losing the single electron in its outermost shell. This loss yields a configuration with more protons than electrons, leading to a net positive charge, thus creating the potassium cation.
Explanation
## Step 1:The formation of a potassium ion starts with a neutral potassium atom. Potassium, represented as (K) on the periodic table, has 19 total electrons when in its atomic state: 2 in the first shell, 8 in the second and 8 in the third shell. However, in its fourth shell, there's only one solitary electron.## Step 2:In order to achieve greater stability, elements seek to fill their outermost (valence) electron shell. The preferred configuration is having 8 electrons in the outermost shell, based on the Octet Rule (the principle stating that atoms are most stable when their outermost shell is full), and the Preferable Transition State, which considers ease and energy efficiency in achieving that state.## Step 3:Given that fact, for potassium the most energy efficient way to a stable electron configuration is to lose this solitary electron rather than acquire seven new ones. ## Step 4:When potassium loses this sole electron from its valence shell, it ends up with more positive protons than negative electrons, thus resulting in an overall positive charge. This process results in the formation of a potassium ion, represented as
in scientific notation.