Unit 1, Topic 2: Atomic Structure and the Periodic Table Flashcards
Define ‘atom’
The smallest particle that cannot be broken down into anything simpler by chemical means
Define ‘isotope’
Atoms that have the same number of protons but different number of neutrons
Define first, second and third ionization energies
- The amount of energy needed to remove 1 electron from each atom of 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions
- The amount of energy needed to remove 1 electron from each ion in 1 mole of gaseous 1+ ions to form 1 mole of gaseous 2+ ions
- The amount of energy needed to remove 1 electron from 1 mole of gaseous 2+ ions to form 1 mole of gaseous 3+ ions
Define ‘orbital’
a place where electrons are likely to be found and one orbital can contain a maximum of 2 electrons which spin in opposite directions
Name the three factors that effect ionization energy
- number of protons in the nucleus
- electron shielding
- energy sub shell for which the electron is removed
Explain how the number of protons, electron shielding, and the sub-shell for which electrons are removed influence ionization energy
- number of protons
- there is a higher nuclear charge, which results in a stronger attraction between the electrons and the protons in the nucleus –> higher IE - electron shielding
- the electrons in the outer shell are repelled by electrons in the inner shell –> weaker attraction –> lower IE - electron sub-shell
- electrons are further from the nucleus –> weaker attraction –> lower IE
What are the shapes of the s and p orbitals?
Spherical and an elongated dumbbell shape respectively
What are the three principles of orbitals?
- Aufball principle
- electrons fill up from the orbital with the lowest available energy level first - Pauli’s exclusion principle
- each orbital can only contain at most two electrons with opposite spins - Hund’s rule
- orbitals fill up singly before electrons pair up
The higher the proton to electron ratio, the stronger the…
attractive forces
Explain the drop of first ionization energy in group 3
- Outer shell electrons fill the p-orbital (2p and 3p), which is higher energy and further away from the nucleus than the outer shell filled in the s-orbital from group 2 (2s and 3s)
- More shielding and further distance between the nucleus and outer shell electrons
–> less attractive forces –> less IE
Explain how the melting point of metals are linked to bond strength and structure
- Metals have electrostatic attraction forces between positive metal ions and delocalized electrons
- Melting point increases across the period as metal-metal bonds become stronger
- This is because the metal ions have an increasing number of electrons and a decreasing radius
- This leads to higher charge density –> lots of energy needed
Explain how the melting point of giant molecular structures are linked to bond strength and structure
- They have strong covalent bonds
- Millions of atoms held together with strong covalent bonds, so lots of energy is needed to break those bonds
Explain how the melting point of simple molecular structures are linked to bond strength and structure
- Their melting point depends on the strength of intermolecular forces between molecules (London forces)
- These forces are easy to overcome –> low MP
Describe the workings of a mass spectrometer
1) The vaporized sample enters the electrical chamber where it is bombarded by high-energy electrons (ionization)
2) The sample’s electrons are knocked out, forming positive ions.
3) These ions pass through slits in the plate, forming a beam
4) Acceleration then occurs where the negative electric field accelerates the ions to high speeds
5) The beams of the positive ions are deflected by the magnetic field (the higher the mass/charge ratio, the less the deflection)
6) The ions reach the ion detector and generate a current which is produced by electrons transferring from the detector to positive ions
7) A mass spectra graph is produced
