Quantum Mechanics
What is the relationship between wavelength and frequency in the electromagnetic spectrum?
Wavelength and frequency are inversely related. As wavelength increases, frequency decreases and vice versa, according to c=λν.
What happens to atomic radius as you move down a group in the periodic table, and why?
Atomic radius increases because new electron shells are added, increasing the size of the atom.
What is the shape of a molecule with four bonding pairs and no lone pairs?
Tetrahedral
calculate the wavelength for a baseball mass (180g) moving 30 m/s
1.23×10^−34 m
How much heat (q) is required to raise the temperature of 100 g of water from 25.0°C to 75.0°C? (Specific heat of water = 4.18 J/g°C)
20.9 kJ
A laser emits green light with a wavelength of 515 nm. Calculate the frequency of this light.
ν=5.83×10^ 14 Hz
Why does atomic radius decrease from left to right across a period?
The effective nuclear charge (Zeff) increases, pulling electrons closer to the nucleus without adding additional shielding.
What is the bond angle in a trigonal planar molecule?
120°
How many orbitals are in a n=4 shell
16
A reaction releases 150 kJ of heat. If this occurs at constant pressure, what is ΔH?
ΔH=−150 kJ
An FM radio station broadcasts at a frequency of 100.2 MHz. Calculate the wavelength of the radio waves.
λ=2.99 m
What happens to ionization energy as you move down a group, and why?
Ionization energy decreases because outer electrons are farther from the nucleus and experience more shielding, making them easier to remove.
What is the molecular geometry of SF4?
Seesaw
How many orbitals are in the l=5 subshell
11
If 200 g of iron (c = 0.449 J/g°C) is heated from 30.0°C to 150.0°C, how much heat is absorbed?
10.8 kJ
Calculate the energy of a photon with a wavelength of 450 nm.
E=4.42×10−19 J
Compare the atomic radii of Na, Mg, and Al. Which is the smallest, and why?
Aluminum (Al) has the smallest atomic radius.
What type of hybridization does carbon have in ethene (C2H4)?
sp² hybridization
what is the electron configurations for Mg
1s2 2s2 2p6 3s2
The combustion of methane releases 802 kJ/mol of energy. How much energy is released when 3.5 moles of methane burn?
2807 kJ
A laser pulse with a wavelength of 532 nm contains 3.85 mJ of energy. How many photons are in the pulse?
1.03×10^16 photons
The element phosphorus (P) has an atomic number of 15. Using the formula Zeff= Z - S, calculate Zeff for a valence electron.
Phosphorus has an effective nuclear charge of ≈5 for its valence electrons.
What are sigma (σ) and pi (π) bonds?
Sigma bonds result from head-on orbital overlap, while pi bonds form from the side-by-side overlap of p orbitals.
What is the electron configuration for Sc
[Ar] 4s2 3d1
How much heat is required to melt 50.0 g of ice at 0°C? (Heat of fusion of ice = 6.02 kJ/mol, molar mass = 18.02 g/mol)
16.7 kJ