Download element symbol on PT

7
N
14.0067
In neutral atom the number of
protons = the number of electrons
-Atomic
Number
-Element
Symbol
-Atomic Mass
Number
• To find the number of neutrons in an atom
you –
1. Round the bottom number to the nearest
whole number
2. Subtract the atomic number from the
atomic mass number. (You will always
subtract the smaller number on top from the
larger bottom number)
Calculating Neutrons
H =
1
1
23Na
11
1 - 1 = 0 neutrons
= 23 - 11 = 12 neutrons
23 (protons and neutrons)
- 11
just protons
12 neutrons
Element
Hydrogen
Helium
Carbon
Nitrogen
Oxygen
Cobalt
Copper
Iron
Uranium
Krypton
Number of
Protons
1
Mass
Number
Number of
electrons
1
1
Atomic
Number
1
Number of
Neutrons
0
Properties of Subatomic Particles
Particle
Symbols
Electron
e--- ,
0
--1
Relative
Electric
Charge
e
-- 1
Mass
Number
Relative
Mass (AMU)
Actual Mass
(Kg)
9.109 x 10--3
0
0.000 5486
Proton
Neutron
p+
1H
1
N0 , o1n
+1
1
1.007 276
1.673 x 10-- 27
0
1
1.008 665
1.675 x 10--27
Remember—
• Protons are Positive
• Electrons are negative
• Neutrons are neutral
29
Cu
63.55
-Atomic Number =
number of protons
-Element
Symbol
-Atomic Mass Number=
number of protons
PLUS neutrons
Isotopes are atoms that have the same number of
protons as another atom but have different number of
NEUTRONS
• Isotopes are atoms that have the same
number of protons as another atom but have
different number of NEUTRONS
Uses of Isotopes
• Medical tracers- Tc (43) used in bone scans
• Carbon-14 “radioactive carbon dating” to
estimate age of very old stuff.