Atomic structure Flashcards
(26 cards)
What are the fundamental particles that make up atoms?
Protons, electrons, and neutrons
Protons and neutrons exist in the nucleus and are sometimes called nucleons.
Where do protons and neutrons exist within an atom?
In the nucleus
Neutral atoms have the same number of protons and electrons.
What is the charge and relative mass of a proton?
+1 charge, relative mass of 1
What is the charge and relative mass of a neutron?
0 charge, relative mass of 1
What is the charge and relative mass of an electron?
-1 charge, relative mass of 1/1840
How can you determine the number of electrons in positive and negative ions?
For positive ions, subtract electrons; for negative ions, add electrons.
What defines isotopes?
Atoms of an element with the same number of protons but different numbers of neutrons.
What is the mass number of an atom?
The total number of protons and neutrons in the nucleus.
What is the relationship between mass number and atomic number, except in hydrogen?
The mass number is normally roughly twice as big as the atomic number.
What technique allows the masses of individual molecules or isotopes to be determined?
Mass spectrometry
What are the five stages of a simple time of flight (TOF) spectrometer?
- Ionisation
- Acceleration
- Ion drift
- Detection
- Data analysis
What happens during the ionisation stage of mass spectrometry?
The sample is dissolved in a volatile solvent and ejected as tiny droplets containing positively charged ions.
What is the purpose of the acceleration stage in mass spectrometry?
Positive ions are accelerated towards a negatively charged plate.
What does the detection stage in mass spectrometry involve?
Ions pick up an electron from the detector, causing a current to flow.
How is the relative atomic mass calculated from mass spectra?
Multiply each isotopic mass by percentage abundance, add the results together, and divide by 100.
How are electrons arranged in an atom?
Into energy levels defined by the principal quantum number, n.
What is the maximum number of electrons in the first four energy levels?
- n=1: 2 electrons
- n=2: 8 electrons
- n=3: 18 electrons
- n=4: 32 electrons
What are orbitals?
Regions around the nucleus that can hold up to two electrons with opposite spins.
What shapes do the first four sets of sub-levels (s, p, d, f) have?
- s: Spherical
- p: Dumbbell
- d: Complex
- f: Complex
What is the order of filling for orbitals based on energy levels?
Electrons fill from the lowest energy first: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p.
What is noble gas shorthand in electron configuration?
Using the previous noble gas notation followed by the remaining configuration.
What is the first ionisation energy?
The energy required to remove a mole of electrons from a mole of gaseous ions.
How does ionisation energy trend down group 2 elements?
It decreases due to increased shielding and atomic radius.
How does ionisation energy trend across period 3?
It increases due to increased nuclear charge and decreased atomic radius.
