Chemistry Flashcards
An n- type semiconductor is a covalent solid in which
the energy gap is very small. the charge carries are negative (electrons)
In a covalently conded solid, the bonding is produced by
Sharing of electrons between adjacent atoms (diamond case or SI)
statements about atomic parking in a crystal lattice
Packing fraction for HCP lattice is the same as for FCC lattice
the intercepts of a crystallographic plane with the three crystallographic axes, x,y,z, are expressed as fractions of the unit cell dimensions along a given direction. Thus, the intercepts of (120)plane are:
(1,1/2,oo)
If the hardening of alloy is induced by diffusion controlled precipitation of second phase particles, then the rate of hardening is
exponentially dependent on temperature
metallic corrosion statements
Iron corrodes substantially when in contact with zinc, in an aqueous environment.
statement about toughness of a material
high hardness is an indication of high toughness
the nucleus of a neutral atom contains 42 protons and 54 neutrons
Monolybdenum
how many protons, neutrons and electrons are in an ion rhodium isotope. 103 Rh3+
atom #=45 (Rh)( periodic table)
atomic mass=103
neutrons= atomic mass-Protons
electrons= protons-3
compound does contain a covalent bond
all compounds with Hydrogen “H” always forms covalent bonds and No is covalent.
Noble gas
find the element in the periodic table and if its negative go right, if its positibe go left and it should end up in the noble gas section if not then is not a noble gas.
equilibrium constant
CO+H2O=CO2+H2
=CO2+H2/CO+H2O
how many valence electrons does an element, arsenic from group 5A have?
element number 33-(accommodate shells 2+8+18)=28
=33-28=5
ground-state electron configuration of a barium ion, Ba2+
look the periodic table
number of electrons 56
the, 56-2=54
the same as Xe
percentage by mass of carbon in the hydrocarbon propane, C3 H8
total=3(12)+8(1)=44
carbon=3(12)=36
%C=100*36/44
