Chapter 6 Ionic Compounds: Periodic Trends and Bonding Theory
PERIODIC TRENDS: 1. ATOMIC RADIUS 2. IONIC RADIUS
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Transcript of PERIODIC TRENDS: 1. ATOMIC RADIUS 2. IONIC RADIUS
PERIODIC TRENDS:1. ATOMIC RADIUS
2. IONIC RADIUS
What is the atomic radius? What is an ion? What is the ionic radius?
How does it change going across and down?
What is a radius?• Half of diameter as measured from center of
circle
What is an Atomic Radius?• half of the distance between the two adjoining
nuclei of atoms
Some elements occur stuck together naturally!
What are the seven diatomic elements?
• Diatomic Elements: two elements joined together
• Bromine (Br2)
• Iodine (I2)
• Nitrogen (N2)
• Chlorine (Cl2)
• Hydrogen (H2)
• Oxygen (O2)
• Fluorine (F2)
Made easy to remember….
Br I N Cl H O F
(like a last name Brinclhof)
Br I N Cl H O F Where are they on the periodic table?
Atomic Radius TrendIn groups = as atomic number increasesIn periods = as atomic number increases
Is there a part missing?
Trends show general rules
WHY?• In groups: adding more energy levels
• In periods: size of nuclear charge
What is an ion?• A ✚ or − charged atom• Occurs when atom loses or gains electrons
CATION• see a + ion• metals lose e- and become more +• become smaller
Atom:11 p+12 n11 e-
n=3
Overall charge = 0
Ion:11p+12 n10 e-
n=2
Overall charge = +1
ANION• A negative ion , a – ion• NONmetals gain e- and become more –• become larger
Atom9 p+9 e-
Overall Charge = 0
Ion9 p+10 e-
Overall Charge = -1
IONIC RADIUS TREND• Ionic size changes b/c:• CATIONS get smaller as e- are drawn in closer by +
nuclear charge
• ANIONS get bigger as e- cloud spreads out
IONIC RADIUS TREND• In groups = increase as you go b/c more energy
levels
• In periods = as you go across b/c e- cloud shrinks as e- are lost