Ions (Pre-IB SC 9)
What shell are the valence electrons in?
Outermost shell
Most elements in the same family have the same number of _____________.
Valence electrons
The period number indicates the number of ___________________.
Shells that have electrons
Why are noble gases unreactive?
They have filled valence shells. (max number of electrons in outer shell)
What do the filled valence shells indicate?
Atoms with filled valence shells have noble gas stability. They cannot lose, gain, or share electrons easily with other atoms to create new substances, so they are stable and unreactive.
What is the pattern of valence electron shells looking at the table?
Elements that are in the same group have the same number of valence electrons in their outermost shells.
What is an ion?
An ______________ that forms on an atom when it ____ or ____ electrons.
Electric charge, gains, loses
What is a negative ion?
An atom that has gained electrons. (extra electrons make it negative.)
What is a positive ion?
An atom that has lost electrons. (The loss of electrons removes negative charge.)
What is the pattern of ion charges in the table?
- Elements on the left tend to form postive ions
- Elements on the right tend to form negative ions
- Elements in same group form ions with same charge as other elements in that group
Ions have the same electron arrangement as the nearest ________.
Noble gas.
Charge on ion = ?
Sum of charges on its protons and electrons
What is the ionic charge of sodium?
1+
What is the ionic charge of fluorine?
1-
What is the ionic charge of argon?
0
How many valence electrons in silicon?
4
How many valence electrons in calcium?
2
How many valence electrons in neon?
8 (full valence shell)
What is the difference between an atom and an ion?
Atom:
- NEUTRAL: #p+ = #e-
ex. (+8)+(-8)=0
- UNSTABLE: v shell not full and it's not a noble gas
Ion:
- CHARGED: #p+ ≠ e-
ex. (+8)+(-10)=-2
-STABLE: v shell is full and it's not a noble gas
Which element does the Cl ion look like?
Ar
Which element does F ion look like?
Ne
Which element does K ion look like?
Ar