Radioisotopes

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Radioisotopes; Chemical Bonding: Ionic Bonding

Radioisotopes:

--> have unstable nucleus and emit subatomic particles or energy as they decay into more stable atoms

--> an isotope that gives off radiation

Radioactive emission include:

Nuclear Radiation

Alpha particles (α) (particles)

---> HELIUM nucleus (two protons & two neutrons will break off an be emitted) (protons and neutrons)

---> stopped by a SHEET OF PAPER (not a high energy also be stopped by skin)

(the particles are really heavy) (internally in body is dangerous, inside can penetrate easier, but not as easy as skin layer)

Beta Particles (ß)

---> High speed electrons

---> stopped by a SHEET OF LEAD

(layer of meta to stop it, dentist x ray, radiation can penetrate into skin)

Gamma Rays (γ) (wave) (no charge)

---> Electric Electromagnetic

---> Radiation can be stopped by a BRICK OF LEAD

(because its a wake it moves at the speed of light, can penetrate very easily

Radioisotopes

ATOMIC #MASS

C 6 C14 trace movements of carbon through biological pathways, like respiration & photosynthesis

Ca 20 Ca 45 measures rate of bone formation

K 10 K 40 Half-life of 1.3 billion years (decay into Ar 40) Ratio of K40: Ar40 use to date fossils

*I 131 I 53 Taken up by the thyroid gland ( takes iodine) . Gland can be imaged to detect abnormalities (regions that don't have access to iodine, radioactive iodine, it migrates to the thyroid)

*Ra 226 Ra 88 Emits radiation that can destroy living cells used to treat cancer tumors (destory DNA, healthy and bad cells destroy)

(I 53Half like because it has half like of 6 hrs)

(K40 radioactive forever)

Half life: amount of time for the substance to decay by half

Radioisotopes in medicine

---> Radiation can damage cells

---> EXTREMELY useful in diagnosis and treatment of diseases

Eg #1 : infect radioactive material into patient and trace its movement in the body

Eg #2: energy emitted from radioactive decay can be directed to a tumor

--> short half-life preferred when it is in or bodies

How to Trace?

--> tracer- radioisotope placed in body on biologically active molecule (glucose, detecting cancer migrate to those areas where cells are using it really quickly water or ammonia)

--> Give off gamma rays as they decay easily detectable

Example: PET scan on a 47 yr old women shows leukemia preset i bone marrow before treatment (left) and chemotherapy (right)

red shows red where there is high glucose uptake

after: green not as much glucose uptake

Brain normal (red is good brain, that is very active, needs glucose)

Cocaine: not functioning good no no red, brain activity slower)

ionization can damage healthy cells, can damage DNA perminatly

Chemical Bonds

Chemical Bonds are formed between atoms by interaction of their respective electrons

These types of INTRAMOLECULAR bonds:

Ionic Bonds

Covalent Bonds

Polar Covalent Bonds

Ionic Bonds

----> occurs when there is a transfer of one or more electrons from one atom to another.

----> electrostatic attractions happen between two opposite charged ions in a ionic bond