Inorganic lecture 1

Question 1

Describe an atom

Answer 1

Atoms consist of a positively charged nucleus surrounded by negatively charged electrons. The nucleus is formed of positively charged protons and neutral neutrons.

Question 2

Describe what determines an element

Answer 2

Elements are determined by their atomic number (Z) ie the number of protons they have in their nucleus.

Question 3

Define atomic mass (A)

Answer 3

The number of protons + the number of neutrons

Question 4

Describe isotopes

Answer 4

Isotopes are atoms of an element with the same number of protons but .a different number of neutrons

Question 5

State the mass of an electron relative to that of protons and neutrons

Answer 5

1/1836

Question 6

Describe an electron

Answer 6

Early experiments showed electrons behaving as particles, with mass m and momentum p. They also have kinetic energy and a property called spin

Question 7

State the equation relating momentum and mass

Answer 7

p = mv
p is momentum
m is mass
v is velocity

Question 8

State the equation for kinetic energy

Answer 8

KE = 1/2mv^2
m is the mass
v is the velocity

Question 9

Describe spin in an electron

Answer 9

Spin refers to the presence of a magnetic moment. For an electron the values spin can take are opposite, not parallel: ±1/2, or described as up and down

Question 10

State De Broglie’s wavelength relationship

Answer 10

λ = h/p
λ is wavelength
h is planck’s constant
p is momentum mv (which demonstrates wave particle duality)

Question 11

Give light’s fundamental properties and state the equation linking them

Answer 11

Wavelength (λ) frequency (f) and velocity (c)

λ x f = c

Question 12

Give the equation for the energy of a photon, ie packet of light energy

Answer 12

E = hf

Question 13

Describe the Rutherford model and why it has been superseded.

Answer 13

There was said to be a central massive nucleus orbited by electrons. Spectroscopy showed that only certain orbits were “allowed” which formed the basis for the Bohr model

Question 14

Describe ᴪ (psi)

Answer 14

ᴪ represents wavefunction:, which is a mathematical function describing behaviour of an electron; it consists of a radial component and an angular component, and describes the behaviour of an e- in an orbital. It refers to the amplitude of an electron

Question 15

Describe what the Schrödinger equation is used for

Answer 15

The SE described the behaviour of electrons in atoms, by treating them as waves. Ie, the SE is a wave equation

Question 16

Describe solutions of the SE

Answer 16

Solutions of the SE are ᴪ (wavefunctions) which describe possible states for an electron.

Question 17

Describe quantisation

Answer 17

Quantisation results directly from boundary conditions, which means only solutions and energies are possible

Question 18

Describe ᴪ^2

Answer 18

ᴪ^2 refers to the probability of an electron being at a certain point, ie the electron density at a certain point.