Atomic Structure - Topic 2

What makes up an atom?

Protons (+), electrons (-), and neutrons (no charge)

Where are electrons in the atom?

They occupy the space outside the nucleus

What is a mass spectrometer?

It is a machine used to determine the relative atomic mass of an element using isotopic composition

What is the nuclear symbol notation?

A↓X↓Z

How do you deduce the number of protons, electrons, and neutrons using nuclear symbol notation?

Protons = Z, Electrons = Z + -Charge, Neutrons = A - Z

What is the formula for determining relative atomic mass?

relative atomic mass = (isotope x natural abundance/100) + (isotope x natural abundance/100)

What is specific evidence for the improvements in scientific equipment?

The alpha particles used in the development of the nuclear model of the atom first proposed by Rutherford

What specific paradigm shift occured?

The subatomic particle theory of matter that occurred in the late 1800s

When is emission spectra produced?

When photons are emitted from atoms and excited electrons return to a lower energy level

What does the line emission spectrum of hydrogen provide evidence for?

The existence of electrons in discrete energy levels, which converge at higher energies

What integer number is given to the main energy shell?

*n*

How many electrons can the main energy shell hold?

2n^2

What are the main energy level divisions of the quantum model?

s, p, d, f (getting progressively higher in energy)

What is a sublevel made up of?

It contains a fixed number of orbital, regions of space where there is a high probability of finding an electron

What characterises an orbital?

Each orbital has a defined energy state for a given electron configuration and chemical environment and holds two electrons of opposite spins

What is the relationship between colour, wavelength, frequency, and energy across the electromagnetic spectrum?

Energy and wavelength are inversely proportional, wavelength and frequency are related by *c=vλ*, colour is a category of wavelength on the electromagnetic spectrum

What is the difference between a continuous spectrum and a line spectrum?

A continuous spectrum is all the colours of the rainbow produced when a white-hot metal object emits a full range of wavelengths (ex. incandescent light bulb filament), a line spectrum is specifically the movement of electrons between energy levels

Describe the light emission of hydrogen.

When an electron in its ground-state and is excited, it moves up an energy level and remains excited for a couple seconds, however when the electron falls down from the excited state, it falls down to a lower energy level and emits a photon, a discrete amount of energy corresponding to a particular wavelength that depends on the differences between the two energy levels in question

What is the shape of the s orbital?

Spherical

What is the shape of the p orbital?

Dumbell, aligned along *x*, *y*, and *z* axes (sometimes called *p*x, *p*y, and *p*z)

What is the Aufbau principle?

This states that electrons fill the lowest energy orbital that is available first

What is the Pauli exclusion principle?

This states that any orbital can hold a maximum of two electrons with opposite spins

What is Hund’s rule of maximum multiplicity?

This states that when filling degenerate orbitals (orbitals of equal energy), electrons fill all the orbitals singly before occupying them in pairs

Write out the filling order for orbitals.

4

4 3

4 3 2

4 3 2 1

3 2 1

2 1

1

s p d f

What illustrates that developments in scientific research follow improvements in apparatus?

The use of electricity and magnetism in Thomson’s cathode rays

What theory has been superseded and by what?

The Bohr model has been superseded by the quantum theory

What theory can explain natural phenomena?

Bohr’s model of the atom and line spectra