Chapter 1: Atomic Structure Flashcards
What energy level are electrons that are further away from the nucleus?
Higher energy because they are higher shells
What energy level are electrons that are closer to nucleus?
Lower energy
What is a valence electron?
Electrons in outermost shell: strong interaction with environment, weak interaction with nucleus; more likely to be involved in bonds with other atoms (have least electrostatic pull from own nucleus)
Definition of atomic mass/mass number?
Is the sum of the protons and neutrons in a given atom of an element
What is an isotope?
Atoms of the same element that have different mass numbers
Definition of atomic weight?
The weighted Average of the naturally occurring isotopes of an element
Planck relation? Equation?
Energy that is emitted as electromagnetic radiation from matter comes in discrete bundles called quanta
E=hf where h= 6.636 x 10^-34 j•s
Angular momentum of an electrons orbit?
L=(nh)/(2pi)
Quantum #•Planck constant / 2pi
So momentum can only change in discrete amounts with respect to the quantum # (the only variable that changes)
Energy of electron? Equation?
E=-Rh/n^2
Rh= 2.18 x 10^-18 J/electron
The energy of an electron increases (becomes less negative) the further away it is from the nucleus (increase in n)
E is directly proportional to n, because as n increases it makes E less negative which in turn in increases E!
Ground state?
State of lowest energy: electrons in lowest possible orbits
Electrons are NOT restricted to specific pathways but they tend to be localized in certain regions of space
Calculate electromagnetic energy of a photon: equations?
E=hf
C=f•lambda
E=hc/lambda
What happens to electrons when they go from a lower energy level to a higher energy level?
They get AHED! Absorb light Higher potential Excited Distant (from nucleus)
Calculating energy of an photon?
E=-Rh(1/ni^2 - 1/nf^2)
Difference in energy between the initial higher energy state and the final lower energy state
Positive E= emission (moved from high to low aka ground state)
Negative E= absorption (moved from low to high level)
Emission and absorption of energy in the form of light
The difference in energy between two shells _____ as the distance from the nucleus _____
Decreases; increases
Principal quantum number (1st)
n
Electrons per shell= 2n^2
The higher n, means higher energy level and radius of electron shell
Angular momentum quantum number (2nd)
l Refers to shape and number of subshells in a shell (n) Max number of electrons per subshell= 4l+2 L ranges from 0 to (n-1) L=0; s L=1: p L=2; d L=3; f Ex. N=4, l=2; 4d subshell
Magnetic quantum number (3rd)
ml
Specifies particular orbital within a subshell
Each orbital can hold 2 electrons max
Between -l and +l
Ex. An l of 3 (f shell) means -3-3 so 7 total orbitals which can hold 14 total electrons
Spin quantum number (4th)
ms
Electron has two spin orientations; +1/2 and -1/2
Electrons in the same orbital must have opposite spins=paired
Electrons in different orbitals with same ms value are parallel spins
Which subshell will fill first?
(N+l) and the one with the lower energy will fill first; if same value than the one with the lower n value will fill first
What is an exception to the electron configuration?
Chromium; it has 4s13d5 rather than 4s23d4
Copper; 4s13d10 instead of 4s23d9
Want a lower energy (higher stability) which is best achieved when orbitals are half filled or fully filled; prefer half full d level than full s level because more stability
Paramagnetic material?
A magnetic field will cause parallel spins in unpaired electrons and cause an attraction
Diamagnetic material?
Atoms that have all paired electrons will be repelled by magnetic field
