Question

complete the steps in the formation of a potassium ion.

1. an atom of potassium has __________ electron

in its __________ energy level.

1. a potassium atom __________ one electron in

its outer energy level when it combines with an iodine
atom.

1. the potassium atom is now an __________.
2. the potassium ion has a charge of __________.
3. the symbol for a potassium ion is __________.

analyze why are group 14 elements much more likely to share
electrons than transfer electrons?
_____________________________________________________
_____________________________________________________
_____________________________________________________
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get it? explain what part of an ion’s symbol indicates its charge?
_____________________________________________________
get it? explain why an atom of iodine tends to react to gain one
electron.

Explanation:

Step1: Recall Potassium Atom Structure

Potassium (K) has an atomic number of 19. Its electron configuration is \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^1\). So, it has 1 electron in its outermost (4th) energy level.

Step2: Determine Electron Behavior

Potassium is a metal in Group 1. Metals in Group 1 tend to lose their single outer electron to achieve a stable octet (like the noble gas argon, \(1s^2 2s^2 2p^6 3s^2 3p^6\)). So, a potassium atom loses one electron in its outer energy level when reacting with iodine (a non - metal).

Step3: Identify the Resulting Species

When an atom loses or gains electrons, it becomes an ion. Since potassium loses an electron, it becomes a positive ion (cation).

Step4: Calculate the Charge of the Ion

The potassium atom has 19 protons (positive charges) and initially 19 electrons (negative charges). After losing 1 electron, it has 18 electrons. So, the charge is \(19(+)- 18(-)=+1\).

Step5: Write the Symbol of the Potassium Ion

The symbol for the potassium ion is \(K^+\), where the superscript +1 (often written as \(K^+\) for simplicity as the charge is +1) indicates the charge.

Analyze: Why Group 14 Elements Share Electrons

Group 14 elements have 4 valence electrons. To achieve a stable octet, they would need to either lose 4 electrons (which requires a large amount of energy as it is difficult to remove 4 electrons) or gain 4 electrons (which is also difficult as adding 4 electrons to a small atom is energetically unfavorable). So, they are more likely to share electrons (form covalent bonds) to achieve a stable electron configuration.

Get It? 1: Ion Symbol Charge Indicator

The superscript to the right of the element symbol in an ion's symbol indicates its charge. For example, in \(K^+\), the \(+\) (or \(+1\)) is the superscript that shows the charge.

Get It? 2: Iodine's Electron Gain

Iodine (I) is in Group 17 (halogens) with an electron configuration that has 7 valence electrons. To achieve a stable octet (8 valence electrons, like the noble gas xenon), it only needs to gain 1 electron. Gaining 1 electron is relatively easy compared to losing 7 electrons, so iodine tends to react to gain one electron.

Answer:

1. An atom of potassium has \(\boldsymbol{1}\) electron in its \(\boldsymbol{outer}\) (or 4th) energy level.
2. A potassium atom \(\boldsymbol{loses}\) one electron in its outer energy level when it combines with an iodine atom.
3. The potassium atom is now an \(\boldsymbol{ion}\) (specifically a cation or \(K^+\)).
4. The potassium ion has a charge of \(\boldsymbol{+1}\) (or \(1+\)).
5. The symbol for a potassium ion is \(\boldsymbol{K^+}\).

Analyze:

Group 14 elements have 4 valence electrons. Losing 4 electrons (to empty the valence shell) or gaining 4 electrons (to fill the valence shell) requires a large amount of energy. Sharing electrons (forming covalent bonds) allows them to achieve a stable octet with less energy input, so they are more likely to share electrons than transfer them.

Get It? 1:

The superscript to the right of the element symbol in an ion's symbol indicates its charge (e.g., in \(K^+\), the \(+\) shows the charge).

Get It? 2:

Iodine is in Group 17 and has 7 valence electrons. It needs to gain 1 electron to achieve a stable octet (8 valence electrons, like the noble gas configuration), and gaining 1 electron is energetically favorable compared to losing 7 electrons, so iodine tends to react to gain one electron.