In the nucleus, this one has 6 protons and 6 neutrons.
In the nucleus, this one has 6 protons and 7 neutrons.
Isotopes are atoms with the same number of protons but a different number of neutrons.
Isotopes have the same atomic number, but different mass numbers
C
C
12
6
13
6
ISOTOPES
Different forms of the same element
What are the features of isotopes?
Most elements have different isotopes but there’s usually only one or two stable ones.
The other isotopes tend to be radioactive, which means that they decay into other elements and give out radiation. This is where all radioactivity comes from – unstable radioactive isotopes undergoing nuclear decay and spitting out high energy particles.
10.1.2.3 explain the nature of radioactivity and the use of radioactive isotopes
Evaluation criteria
knows the nature of radioactive radiation
able to make equations of reactions of radioactive decay.
RadioActivity – What is it?
All substance are made of atoms. These have electrons (e) around the outside, and a nucleus in the middle. The nucleus consists of protons (p) and neutrons (n), and is extremely small. (Atoms are almost entirely made of empty space!)
In some types of atom, the nucleus is unstable, and will decay into a more stable atom. This radioactive decay is completely spontaneous. The energy that is released from the nucleus of the atom is radiation.
RadioActivity – What is it?
RadioActivity – Alpha Particles
RadioActivity – Beta Particles
RadioActivity – GAMMA WAVES
RadioActivity – SUMMARY
ISOtope notation
Isotope Notation includes additional information about an isotope. In addition to the chemical symbol, the mass number and the atomic number are included. This allows information about the nucleus to be determined.
NUCLEAR DECAY REACTIONS
SOME Elements are naturally unstable
they tend to undergo alpha-decay or beta-decay to become more stable.
They may take several steps in order to achieve this, thus we observe decay chains (also known as series decay) for most radioactive elements.
For example, it takes U-238 14 steps of alpha and beta decay to become completely stable
As you go down, e- are filled into orbitals that are farther away from the nucleus (attraction not as strong)
Periodic Trend – As you go across a period (L to R), atomic radius decreases
As you go L to R, e- are put into the same orbital, but more p+ and e- total (more attraction = smaller size)
Ionic Radius
Ionic Radius –
size of an atom when it is an ion
Ionic Radius Trend
Metals – lose e-, which means more p+ than e- (more attraction) SO…
Cation Radius < Neutral Atomic Radius
Nonmetals – gain e-, which means more e- than p+ (not as much attraction) SO…
Anion Radius > Neutral Atomic Radius
Ionic Radius Trend
Group Trend – As you go down a column, ionic radius increases
Periodic Trend – As you go across a period (L to R), cation radius decreases,
anion radius decreases, too.
As you go L to R, cations have more attraction (smaller size because more p+ than e-). The anions have a larger size than the cations, but also decrease L to R because of less attraction (more e- than p+)