2. Atomic Structure Flashcards
What does 0K refer to?
A complete absence of thermal energy.
How do you convert from degrees C to Kelvin?
Add 273
Define ‘element’.
One type of atom.
Define ‘compound’.
Two or more elements that are chemically bonded.
Define ‘mixture’.
Two or more elements that are not chemically joined.
What is a homogeneous mixture?
A mixture which has the same proportion of components throughout the sample.
What is a heterogeneous mixture?
A mixture where the composition of components is not uniform.
Why can mixtures be separated by physical means?
Each component has unique properties.
Define ‘mass number’.
The number of nucleons.
Define ‘atomic number’.
The number of protons.
What do A and Z refer to?
- A= mass number.
- Z= atomic number.
Define ‘isotope’.
Different variations of an element which have different mass numbers, but the same atomic number.
Why do isotopes of an element react identically?
They have the same number of protons and electrons.
Define ‘relative atomic mass’.
The weighted average mass of an atom of an element, taking into account naturally occurring isotopes, relative to the mass of 1/12 the mass of a carbon-12 atom.
What machine measures isotopic abundance?
Mass spectrometer.
What are the first two groups of elements known as?
The s block
What are the transition metals known as?
The d block.
What are the group 3-8 elements known as?
The p block.
State the Aufbau principle.
Electrons fill lower energy atomic orbitals before filling higher energy ones.
State the Pauli exclusion principle.
No more than two electrons can occupy the same orbital and two electrons from the same orbital have opposite spins.
State Hund’s rule.
Electrons always enter an empty orbital before they pair up.
What is noble gas formation?
Assumes that up to the noble gas is full.
What is the shape of the s orbital?
Spherical
What is the shape of the p orbitals?
Dumbbell shaped.
What is the electron configuration of copper?
[Ar] 3d10 4s1
What is the electron configuration of chromium?
[Ar] 3d5 4s1
