nucleus is made up of protons, neutrons and electrons.
proton mass = 1.67E-27kg
proton chrg = +1.6E-19C
neutron mass = 1.67E-27kg
neutron chrg = 0C
electron mass = 9.1E-31kg
elecrton chrg = -1.6E-19C
z is the atomic number and is equal to the number of protons.
A is the atomic mass and is equal to the atomic number + neutrons.
isotopes are atoms with the same number of protons but different number of neutrons.
AMU = 1/12(mass of carbon isotope 12c) = 1.66E-27kg
Na = 6.02E23 atom/mol
1AMU*Na = 1g/mol
4 quantum numbers
1)- n is the principal quantum number, the shell numbers n=1,2,3,4.
. n=K,L,M,N for 1=K.
2)- l signifies subshell and is related to quantification of angular momentum, also gives
..(n-1) l=s,p,d,f for 0=s.
3)- orientation of subshells me= (-l),(-l+1).
.-1,0,1,2,+l (a total # of 2l+1values)
4)- ms spin momentum = -.5, +.5
principal quantum #,
e per subshell.
a-melting temp, large Eo (bonding energy_ results in high melting temperature.
b-mechanical stiffness (electrostatic models) shape represents stiffness a very steep curve represents high stiffness, a shallow curve
represents a flexible material.
c-thermal expansion a steep and deep curve represents a low thermal expansion.
transition incomplete d sub shell
inert filled s an p 3s23p6
halogen one e- different from filling 2s2 2p5
alkaline earth s2 ; alkali single e-
Fa = (z1e)(z2e)/[(4πξ
4 quantum numbers are used to characterize the electronic states
Atomic number gives total number of electrons in neutral atom
In an electrically neutral atom the number of electrons is equal to the number of protons.
Ionic bonding is found in metallic and non metallic elements. Atoms obtain stable configurations similar to that of the noble gases. Found at
the extremes of the periodic table. Strong interaction between components, high melting points, electric insulators, have low thermal
conductance, non-directional bonding. Bonds are generally strong 50 ▫
Covalent bonding has stable configurations which are achieved by sharing electrons between neighboring atoms. Covalent bonds can be
directional, have directional interatomic bonding. Covalently bonded materials are insulators with generally strong 50 kj/mol
1500 KJ/Mol bonds. Covalently bonded materials are less dense than metallic or ionically bonded ones because covalent bonds are
directional in nature whereas metallic and ionic are not; when bonds are
Structure of crystalline solids. Crystalline materials are formed when atoms are arranged in repeating array. Occurs in amorphous materials
where there is no long range order. A lattice is a 3d array of points. The unit cell is a small group of atoms which by many of them in a
repeated manner generates the entire crystalline structure.