ch. 4 Flashcards
(46 cards)
an atom is made up of what? define with charges
nucleus that hold neutrons (0) and protons (+) and electrons (-) float around the nucleus
each atom has equal number of
protons and electron
number of protons is determined by? number of protons AND neutrons are determined by?
number of protons (and electrons); atomic number or z
the number of protons AND neutrons: atomic mass A
what formula can be used to find atomic mass? where is atomic # and mass found on p table?
A= z(p)+n . the top number on element is atomic number and bottom number is mass number
what is an isotope? what is an atom with 7 neutrons with a mass of 12
an isotope is 2 atoms of same element differing in number of neutrons. THEY HAVE SAME ATOMIC NUMBER BUT DIFFERENT MASS NUMBER. ANSWER is Boron because it has 5 protons
what is the atomic weight of an element? what is an ion?
atomic weight: weighted avg of the masses of its occurring isotopes
ion: when a neutral atom losses of gains electron (cation=(+) and anion=(-)
protons and neutrons are held by? unstable nuclei are called?
P and N’s are held by strong nuclear force and the unstable nuclei are radioactive
what is radioactive decay? what are the three main types of decay?
radioactive decay is the changes an atom goes through to lower its energy. the three kinds of decay are alpha, beta, and gamma
what is the parent and daughter in radioactive decay
parent is radioactive unstable nuclei while the daughter is more stable nuclei
what is alpha decay?
large nucleus becomes more stable by emitting an alpha particle which is 2 protons and 2 neutrons. A-4 and Z-2
what are the three types of beta decay?
beta - decay, beta + decay (positron emission) and electron capture
what is beta - decay
converts a neutron into a photon and electron called a beta - particle. ATOMIC NUMBER INCREASES BY ONE AND MASS NUMBER STAYS THE SAME
what is beta + decay
converts protons into a neutron and a positron (and electron antiparticle) ATOMIC NUMBER IS ONE LESS AND MASS NUMBER STAYS THE SAME
what is electron capture
increases the number of neutron to capture an electron. causes ATOMIC NUMBER TO BE REDUCED BY 1 AND MASS NUMBER STAYS THE SAME (nothing is ejected rather something is added)
what is gamma decay
a nucleus after going through alpha or beta emits a photon (gamma photon) VERY RADIOACTIVE BUT DOESNT CHANGE ATOMIC OR MASS NUMBER THEREFORE NO IDENTITY CHANGE
what is half life, what are the percent after each hour from 1 hour to 4
time it takes for 1/2 decay. 1 hour: 50% (1/2), 2 hour: 25% (1/4) 3 hour: 12.5% (1/8) 4 hour: 6.25% (1/16)
cesium has half life of 30. how long does it take for 0.3g to remain from 2.4g
0.3/2.4= 1/8 meaning three half lives 3(30)=90
what is emission spectrum
gas that when light shines through, itll separates the light into its component wave length.
bohr models show what about jumping electrons?
absorbed: electron jumping to higher level is (+) energy as photon absorbed
emission: electron jumping to lower level is (-) with photon emission
what is the quantum model state
orbitals is where electrons are found in subshells s, p, d, and f
what are the 3 rules for filling orbitals? define each one with its principle
- aufbau principle: electron occupy lowest energy orbital first and it fills in order of increasing order
- hunds rule: electron in same subshell occupy available orbitals by themselves before pairing up
- pauli exclusion principle: there can be no more than 2 electrons in any given orbital
how many electrons can each S, P, D, F? what is electron configuration of Neon
S=2
P= 6
D=10
F= 14
Neon= 10 electrons 1s^2 2s^2 2p^6
what is diamagnetic? paramagnetic?
diamagnetic: atoms with all electrons paried up and repels magnetic field
paramagnetic: atoms that dont have electrons paired up and attracted to magnetic field
where can you find the s block, p block, d block, and f block
s block: first two columns d block: middle horizontal lines p block: last 6 columns f block: bottom two rules
