Atomic structure

What do the horizontal segments of the heating curve show?

The Change of state, as this is when intermolecular forces are being broken

How is absolute temperature expressed?

Kelvin

How do you calculate absolute temperature?

Temp°C + 273

How can you tell if a substance is pure or impure?

Pure substances have a sharp boiling point whereas impure substances have a lower boiling point with a range

What did Rutherford conclude in his Gold Foil experiment?

Atoms are mostly empty space as most alpha particles went straight through the foil

A very small number of alpha particles being deflected at large angles suggested that there is a concentration of positive charge in the atom

The very small volume of alpha particles coming stright back suggested that the positive charge was concetrated in a tiny volume in the atom (the Nucleus)

What does the mass number show?

The number of protons and neutrons

What does the Atomic number show?

The proton number

What is one atomic mass unit?

1.66x10^-24

What is an isotope?

Atoms with the same number of protons but different number of neutrons

What is the relative isotopic mass?

The mass of the isotope relative to Carbon-12

What is the relative atomic mass?

The average mass of all the isotopes of an element

Taking into account the percentage abundance

Relative to Carbon-12

What can often happen in a mass spectrometer?

The molecule ions produced in mass spectrometers have so much energy that they can fragment as well as ionise

What is the Aufbau Principle?

Add electrons progressively starting with the shells closest to the nucleus

What does the number of occupied shells indicate?

The period number

What does the number of electrons in the outer shell indicate?

Group number

What are Ions?

Charged atoms or a group of charged atoms