General Chemistry: Chpt 4 (Atoms, isotopes, atomic weight, ions, configurations, models, periodic trends, excited/ground states Flashcards
The nucleus contains_______ and ______, which collectively are called:
protons and neutrons; nucleons
In a neutral atom, what is equal?
protons and electrons
Atomic Number - define and list symbol
Z: Determines element of the atom; # of protons
The mass in an atom is concentrated, and the numerical kg number is:
In the nucleus : the protons + neutrons in the nucleus = 1 amu = 1.66 x 10^-27
Atomic Mass - define and list symbol
A: Number of protons + neutrons
A = Z + N
Define Isotopes
2 atoms with same element different number of neutrons
True or False: Isotopes have the same mass #
Yes
The atomic mass unit (amu) is = ?
amu= most abundant isotope of carbon, C-12 = 12 amu exactly
Atomic weight: define and state how to mathematically determine
Weighted avg. masses naturally occuring isotopes - use percents of each and multiple
Ion: Define
A neutral atom that has gained or lost electrons - becomes charged
When an atom gains electron(s), the charge is ____ and it is called _______
-, anion
When an atom loses electron(s), the charge is ____ and it is called _______
+, cation
The energies of the levels of a bohr atom is given in what equation?
En = (-2.178 x 10^-18 J) / n^2
Since we are able to calculated the energies of the levels of a Bohr Model,
(En = (-2.178 x 10^-18 J) / n^2)
what can we now predict? Explain math wise how it is predicted
The wavelengths of photons emitted or absorbed when electrons transition between any two energy levels by subtracting initial energy of the electrons from the final energy of the electrons
Bohr energies are negative when:
Electrons fall from excited to lower energy level (energy released)
Bohr energies are positive when:
Electron transitions from ground to excited, (energy is absorbed)
Formula relating energy of photon to wavelength
DeltaE = h c/wavelength
What is the limitation of the Bohr Model and How does the quantum model deal with this?
Bohr model only deals with one electron/assumes electrons are independent of each other and therefore electron-electron interactions cannot be described in the this model. The quantum model accounts for this by describing “unique” addresses for each electron (4 quantum numbers) designating shell, subshell, orbital, and spin
Describe what happens to the electrons after a photon is absorbed
p. 63, part 4.5
Aufbau Principle
Electrons occupy the lowest energy orbitals available
Hund’s Rule
Electrons in same subshell occupy available orbitals singly BEFORE pairing up
Pauli Exclusion Principle
There can be no more than 2 e- in any given orbital
List max. amount of electrons that can go into any subshell:
s
p
d
f
s: 2
p: 6
d: 10
f: 14
Configure the electron configuration of argon, Ar
1s2-2s2-2p6-3s2-3p6
