Ch 2 Flashcards
(41 cards)
What is most of an atom comprised of?
Most of the atom is composed of empty space because the electrons travel extremely far away from the nucleus
Are atoms devils able and visible?
Yes they are. You can see an electron with a piezoelectric tube with electrodes
What are protons, and neutrons made of? And what is its size?
They are both made of quarks which have the size of 10^-16 cm
Objects made of quarks are called hadrons. Both of these are composed of 3 quarks and therefor called baryons(a subclass of hadrons)
Electrons are leptons and not known to be made up of any sub particles.
About how much lighter are electrons than protons and neutrons?
About 2000 times lighter
What is the smallest particle that will retain an objects chemical properties?
An atom
How is the atomic number calculated?
By summing up the number of protons and number of electrons
How is the atomic mass found?
By summing the mass of the protons, and the mass of the neutrons
What proportion of the mass of carbon is one amu equal too?
1/12 the mass of carbon
What are the units for (average) atomic weight?
Amu/atoms and g/mol
What is an isotope?
Atoms with the same atomic number, but a different atomic weight because of a different number of neutrons.
What is the (average) atomic weight?
The average atomic mass of all naturally occurring isotopes
How many atoms are in one amu?
6.022x10^23 or avrogadros number
Why are atomic weights generally not integers?
Because the atomic masses of atoms are normally not integers
The atomic weight is taken as the weighted average of all naturally occurring isotopes
How much do electrons, protons, and neutrons weight?
Electrons weigh 9.11x10^-31 kg
Protons and neutrons weigh 1.67x10^-27 kg
What are the group 1 and group 2 elements called? What about the d block elements? P block? Group 7 elements? Group 8 elements? F block elements? What are the metalloid elements?
Group 1= alkaline metals
Group 2= alkali earth metals
D block = transition metals
P block = non metals
Group 7= halogens
Group 8= noble gasses or inert gasses
F block= rare earth series
The metalloid include: B, C, Si, Ge, As, Se, Te
What is the difference between the Bohr atomic model and the schrodinger wave mechanical model?
The both model:
Electrons are assumed to revolve in discrete (specific distances) orbitals around the nucleus
Energies of electrons are quantized, that is electrons can only have certain values of energy.
Electrons can make quantum jumps to change energy. Higher levels of energy=absorb energy, lower levels= emit energy
Schrodinger wave mechanical model:
Position of an electron is described by the probability(pitch fork squared) distribution of electron clouds around the nucleus
4 quantum numbers are used to characterize each electron in an atom
It doesn’t say exactly where the electron is, but where the best probability of finding it is.
Electrons have both particle and wavelike characteristics
What are quantum numbers, and what does each one stand for and describe?
Quantum numbers describe size, shape, and spacial orientation of an electron probability distribution.
(N) the principal quantum
- Designates the size and principal electron shell
- this is the only quantum number associated with the Bohr model
(L) azimuthal quantum number
- sometimes called angular momentum an
- designates the subshell(the shape of the orbital)
- l=n-1
- have names(s,p,d,f)
- the value l tells you how many nodes there are in the probability distribution of the orbital
- also describes the bonding angle, direction of bond in molecules
(Ml) magnetic quantum number
-gives the number or electron orbitals and their orientations
(Ms) electron spin quantum number
- determines the spin of the electron…either -1/2 or +1/2
- the spin of the electron is the minimum angular momentum needed to stay stable
- 2 electrons per orbital
What does the Pauli exclusion principle state?
Each electron state can hold 2 electrons and must have opposite spins
What does hands rule state?
Every orbital must be filled once in all the same direction(electrons with the same spin) before you can fill them in the other direction
How many electrons can be held in the s,p,d,f orbitals?
S=2
P=6
D=10
F=14
What is considered a ground state atom?
One that fills its orbitals from the first orbital (1s) and then work its way up obeying all the rules
What is an excited state atom?
When an electron fills a higher orbital before a lower one, or skips an orbital
Which properties do valence electrons determine?
Chemical, electrical, thermal, and optical properties
What classification do most of the elements on the periodic table come under?
Most of them come under the metal classification. These are sometimes referred to as electropositive elements, because they are capable of giving up their few valence electrons to become positively charged ions.
The elements on the right side of the periodic table are called electronegative elements, because they are ready to accept negatively charged ions, or sometimes they share with other atoms.
