Unit 1 Flashcards
What are quantum numbers
a set of 4 numbers that identifies each electron within an atom-n, I, MI, MS
Pauli’s exclusion principle?
No two electrons can have the same quantum numbers (one up one down)
What is aufbau’s principle
Start from the 1s orbital and go up while completing energy level diagrams
What is Hund’s Rule
To fill orbitals with similar energy before starting to pair electrons
What is the exception to the Cu and Cr columns in D Block
the D shell must always be half full or completely full by moving an electron from another shell (Usually S)
What are the rules for transition metals?
Never touch P orbital
How do like atoms share electrons in covalent bonds
Equally share
What is electronegativity
The relative ability for atoms to attract electrons
What are the stages of the flame test and what happens
Before the flame test, the atom is at its ground state and nothing is happening. during the flame test, the atom is excited and absorbs the energy of the flame, after the flame test, the atom is returning to its ground state and during that process light of a certain wavelength is emitted.
What is the pattern between wave length and energy
As wavelength of light increases, energy decreases and vice versa
What conclusion can be made on the electromagnetic spectrum
Based on the visible aspect of the spectrum, radiowaves (found on the left side of the spectrum) have the lowest energy but the longest wavelengths and gamma waves (found on the right) have the highest energy and the shortest wavelength.
Why are different colours seen in different cation flame tests
the difference in the wavelength emitted from the atom when excited
What are the two types of intermolecular forces
Dipole-Dipole and London Dispersion Forces
What is hydrogen bonding
A type of Dipole-Dipole force that relies on the bonding of a hydrogen atom to one of: O, N, F of another polar molecule.
What molecules are london dispersion forces in between?
Between All Atoms/Molecules
What is happening in Dipole-Dipole Attraction
As electronegativity gives molecules oppositely charged poles, when these molecule come together to create a bigger compound, they arrange themselves in a way that maximizes attractive forces and minimizes repulsive forces (-ve attracts +ve)
Types of Dipole-Dipole
Instantaneous Dipole, Hydrogen Bonding, Ion Dipole
What is an instantaneous Dipole
Molecules with temporary dipoles can induce a dipole in a nearby molecule because of its charged properties at that instant, only 1% as strong as covalent or ionic bonds
What is key about hydrogen bonding
Strongest dipole-dipole force as well as in general for intermolecular forces, binds only to O, N, or F, because of their high electronegativities
What happens to boiling point of a molecule held by hydrogen bonds
Strong forces increases BP
What can be said about the relative strength of London Dispersion forces
Increase with size of molecule, however are not strong in general. More electrons and protons means stronger force
What are Ion Dipole Forces
Forces typically found in aqueous solutions of ionic compounds, such as salt water. strongest intermolecular force
What is interesting about london dispersion forces
Occurs in all molecules non polar or polar
What is viscosity
The resistance to flow. Stronger antiparticle forces, means more viscous liquid
What is beading
Desired for car washing (strong cohesive forces)
What is wetting
Desired for dishwasher, strong adhesive forces
What are composites
Materials made of 2 or more substances, usually light, corrosion, heat and chemically resistant
What are ionic crystals
Electrostatic attraction between atoms create a crystal structure. Brittle, hard, sometimes soluble in water. Conducts electricity when dissolved, High BP and MP
What are metallic crystals
Held together by a sea of electrons. Malleable, lustrous, conduct electricity, and hard.
What are the metallic properties
Sheen - valence e- absorbs and emits light at different wavelengths
Malleability - “electron sea” allows atoms to slide over each other
Conductivity - produces electric current when connected to a source
Hardness - “electron sea” produces strong electrostatic attractions that hold nuclei together
What is a molecular crystal
Crystal held together by weak intermolecular forces (CO2, iodine, water sulfur). Low MP, some hardness, non-conducting
What is a covalent network
Network of atoms held together by covalent bonds (diamond, quartz), hard, High MP, BP, usually non-conductive
Strength from strongest to weakest solid forces
Covalent Network (strongest), Ionic and Metallic (similar), London Dispersion/Molecular Crystal (weakest)
What are application of quantum mechanics
Lasers (stimulation of light into coherent waves), Spectroscopy (Light from stars), MRI (magnetizing water in body), Quantum computing, location services
In a laser with misaligned mirrors, what happens
The waves will be out of phase, with non-synchronizing peaks and troughs meaning instead of creating coherent waves, there will be destructive interference according to the principle of wave superposition.
What makes MRI better than XRAY and CT SCANS
MRI does NOT use ionizing radiation which even though are small amounts in CT and XRAY, are known to cause cancer. MRI minimizes the risks of having a body scan.
Properties of metals
Malleability, conductivity, Hardness due to electrostatic attraction holding nucleus together, High MP and BP due to delocalized electrons
Two molecules, CH4 and C4H10 have different molecular masses, C4H10 being 5x more. Explain why CH4’s BP is -161 and C4H10’s BP is -1
Both of these hydrocarbons are chains. As chain length increases, so does the molecule’s surface area. The bigger the molecules, the stronger the London dispersion forces meaning higher boiling point due to the stronger bonds. This is why the smaller hydrocarbon chain vaporizes first.
