Week 1 (Energy and length scales. Atoms composition)

Question 1

Whats matter?

Answer 1

Anything that has mass and takes up space (volume)

Question 2

Categories of Matter

Answer 2

Pure substances (only one type substance)

Mixture (more than one type substance)

Question 3

Pure Substances (2)

Answer 3

Element (one type atoms)

Compound (more one type atom)

Question 4

Mixture (2)

Answer 4

Homogeneous (uniform composition)

Heterogeneous (irregular composition)

Question 5

Define an Atom

Answer 5

Smallest possible unit into which matter can be divided, while still maintaining its properties.

Question 6

Atomic Strucutre:
what are the two basic components in every atom

Answer 6

Electron cloud
Nucleus

Question 7

What are the 3 subatomic particles:

Answer 7

Proton
Neutron
Electron

Question 8

Protons (6)

Answer 8

• Positively charged particles
• Help make up the nucleus of the atom
• Help identify the atom (~ an atom’s DNA)
• Equal to the atomic number of the atom
• Contribute to the atomic mass
• Equal to the number of electrons

Question 9

Neutrons (3)

Answer 9

• Neutral particles; have no
  electric charge
• Help make up the nucleus of
  the atom
• Contribute to the atomic mass

Question 10

What do quarks make up?

Answer 10

Particles that make up protons and neutrons

Question 11

Charge of an up quark:

Answer 11

+2/3

Question 12

Charge of a down quark:

Answer 12

-1/3

Question 13

Electrons (7)

Answer 13

• Negatively charged particles
• Found outside the nucleus of the atom, in the
  electron orbits/levels; each orbit/level can
  hold a maximum number of electrons
  (more on this next week)
• Move rapidly mainly around the nucleus ~ an
  electron cloud
• Mass is insignificant when compared to
  protons and neutrons
• Equal to the number of protons
• Involved in the formation of chemical bonds
• Most important for chemistry

Question 14

Sub-Atomic Particles
Wieght Comparison

Answer 14

Neutron = 1.6749286 x10-27 kg

Proton = 1.6726231 x10-27 kg

Electron = 9.1093897 x10-31 k

Question 15

Length comparison (metres):

Answer 15

Atom = 10^-10

Nucleus = 10^-14

Proton or Neutron = 10^-15

Electron = 10^-18

Question 16

Wavelength is inversely proportional to …

Answer 16

energy of wave

Question 17

Frequency is directly proportional to …

Answer 17

energy of wave

Question 18

Why is it the W=wavelength light using has to be similar to that of the part matter you’re trying to probe?

Answer 18

Each region EM spectrum of light, interacts with matter different ways.

Question 19

UV photons and upwards are …

Answer 19

• ionising
• dangerous
• excite core electrons

Question 20

Forces in atoms:

Answer 20

• Gravitational (only one, not described by standard model)
• Electromagnetic
• Strong Nuclear Force
• Weak Nuclear Force

Question 21

Gravitational Force:

Answer 21

force attraction of objects due to their masses (amount depends on their masses and distance , not significant force, holding atoms).

Question 22

Electromagnetic Force:

Answer 22

resulting from repulsion like charges, attraction opposite. It holds electrons around nucleus.

Question 23

Strong Nuclear Force:

Answer 23

Holds atomic nucleus together.
Counteracts the electromagnetic force (protons repelling).

Question 24

Weak Nuclear Force:

Answer 24

Plays key role in possible changes, sub-atomic particles.
Responsible, radioactive decay (process, were nucleus of radioactive unstable atom releases nuclear radiation). Original particle changes, something new.

Question 25

We can’t ask where is the electron right now, ask in this particular part of space if I look for the electron what’s the likelihood I’ll find it there, electrons can be placed (different probabilities)

What equation do we use?

Answer 25

Schrödingers equation, calc the electrons probability wave, can predict were percentages of where the electron will lie with high certainty.

Everything in the universe (atoms / matter) runs on probability and not certainty. Determined by chance