Atomic Structure

Question 1

whare are elements and atoms made of

Answer 1

• elements are mode of atoms
• atoms are made of protons, neutrons and electrons

Question 2

when is an atom stable

Answer 2

when it has equal numbers of protons and neutrons

Question 3

what is Mass Number vs Atomic Number

Answer 3

mass number (A) = protons + neutrons

atomic number (Z) = number of protons

Question 4

what determines chemical properties & isotopes

Answer 4

protons determine chemical properties

neutrons determine isotopes

Question 5

what are the components of an atom

Answer 5

proton (+), neutron (neutral) and electrons (-)

Question 6

what are quarks

Answer 6

• elementary particles that never exist alone.
• there are up and down quarks that combine to form protons and neutrons

Question 7

what are electron shells/what do they do

Answer 7

they orbit the nucleas, max electrons = 2(n²)

energy depends on shell and atomic number

Question 8

how does electron energy change

Answer 8

by electrons moving between shells releasing energy
> difference in binding energy and varies per element

Question 9

isotopes vs nuclides

Answer 9

isotopes = different neutrons, same Z

nuclides = excited nucleas, same Z&A

Question 10

why are isotopes/nuclides unstable

Answer 10

they can only become stable via radioactive decay

Question 11

what are the types of radioactive decay

Answer 11

1. alpha
2. beta
3. gamma

Question 12

what is alpha, beta and gamma decay

Answer 12

alpha = 2p+2n- Z = -2 and A = -4

beta (-) = electron + proton-Z+1, and A doesnt change

beta (+) = positron + neutron- Z-1, and A doesnt change

gamma- energy only, no Z/A change

Question 13

what is a decay chain

Answer 13

a series of emissions to reach stability

Question 14

what is half life

Answer 14

the time it takes for half atoms to decay

Question 15

what is the wave-particle duality of electrons

Answer 15

Electrons orbit in discrete orbits but act as waves; de Broglie wavelength λ = h/mv.

Question 16

why does atomic structure matter in imaging

Answer 16

X-rays = e⁻ interactions in tube/tissue

NM = gamma ray detection

MRI = magnetic fields of atoms

Question 17

xray production vs imaging

Answer 17

production = high speed electron interacts with atom

imaging = x-ray photons interact with atoms in tissue

Question 18

what is the MRI principles

Answer 18

• atoms generate magnetic fields due to electron/nucleus movement; used to produce images

Question 19

what is the nuclear med principle

Answer 19

• detects gamma rays from radioactive decay of isotopes; SPECT/PET cameras

Question 20

what is the ‘whats inside the box’ theory

Answer 20

• physicists use models (theoretical/visual) combining formulas & observations
• these models dont equal absoulte truths

Question 21

what are some important historical models

Answer 21

1. rutherford (1911)
2. bohr (1913)
3. faraday (magnetic fields
4. de broglie (wave properties

Question 22

what is the energy of electrons in orbit

Answer 22

Electrons occupy quantised energy levels (shells).

Electrons closer to the nucleus have higher binding energy and lower orbital energy.

When an electron moves to a different shell, it releases or absorbs energy equal to the difference in binding energies.

Question 23

what happens to protons and neutrons when quarks are involved

Answer 23

up + down quarks from hadrons means protons = 2up + 1 down

neutrons = 2 down + 1up