Ions

Getting good study habits

What is an ion?

An atom or a group of atoms that has an electrical charge, either positive or negative

What charge does an atom have?

Neutral

How does an atom become an ion?

By losing or gaining (an) electron(s)

Why do atoms become ions?

To obtain a full valence shell of electrons and become stable

When are atoms unstable?

When they have an incomplete valence shell

What is a valence shell?

The outermost shell of an atom

What is the difference between an atom and an ion?

An atom always has a neutral charge, but ions have either a positive or negative charge

What is a valence electron?

An electron in the outermost shell of an atom

If a sodium atom has one valence electron, how will it become an ion in the most energy-efficient way?

It will lose one atom

If a sodium atom loses an electron, what will its charge be?

Positive

If chlorine has 7 valence electrons, how will it become an ion in the most energy-efficient way?

It will gain one electron

If a chlorine atom gains an electron, what charge will it be?

Negative

What is the difference between drawing a Bohr model of an atom versus a Bohr model of an ion?

A Bohr model of an atom has the atom symbol and the number of protons and number of neutrons written out. Then each shell is filled with the number of electrons, which is the same number as the number of protons (the atomic number). An ion is drawn the same way, but it has a full valence shell and it has square brackets around the model. It also has the ion charge written on the outside of the brackets. The ion charge is always written as number, then charge, not charge then number. Ex. it is 2+ NOT +2. Any additional electrons that were added are drawn in the opposite way as the original electrons. Ex. If you draw your electrons as dots, any added electrons in the ion should be drawn as X's.

Where do extra electrons come from when an atom turns into an ion by gaining an electron?

It comes from another atom that donates it's electron

What charge will an ion have if it loses an electron and why?

It will be positive because it has more protons than electrons

What charge will an ion have if it gains and electron and why?

It will be negative because it has more electrons than protons

Why do argon atoms not form ions?

Because it already has a full valence shell

Why can't carbon atoms form ions?

Because it has four valence electrons, it is in the middle. It would take a lot of energy to lose or gain four electrons.

Why do some elements have multiple ion charges?

Because they can form ions in more than one way

What charged ions do metals tend to form?

Positive ions

What charged ions do non-metals (excluding noble gases) tend to form?

Negative ions

What charged ions do elements in the same group often form?

Elements in the same group often form ions with the same charge