Mixtures & Pure Substances
What is a pure substance?
comprised of one thing throughout
What is the number above the element symbols on the periodic table called and what does it represent?
The Atomic number = # of protons.
What is a cation ion and does it have too many or too few electrons?
positive ion, Too few
Which type of bond is the sharing of electrons in single, double, and triple bonds?
covalent
Draw the lewis structure for CH4. What molecular geometry is it?
Tetrahedral
What is the difference between a heterogeneous mixture and a homogeneous mixture?
homogeneous - the same throughout
heterogeneous - different throughout.
What are the columns of the periodic table called?
groups or families
Phosphorus has a mass number of 31 and an atomic number of 15. How many neutrons does Phosphorus have?
16
What is the formula of Lithium Oxide
Li2O
Draw the Lewis Structure ofr H2O. Is it polar or nonpolar?
Polar, because of the angular molecular geometry.
What is a compound?
atoms of different elements chemically bonded together
How many valence electrons does Carbon Have and what ionic charge does it form?
4, none
Planck discovered that atoms emit light in discrete specific frequencies that can be seen as ________ spectra
line
Name NO2
Nitrogen dioxide
Draw PCl3. What is it's molecular geometry?
Trigonal pyramidal
What is an element
A pure substance that cannot be divided into something new.
Boron or Gallium
Einstein proved that light is made up of ________ called photons
What is the formula of Dinitrogen trioxide
N2O3
Draw the lewis structure of CO. What type of bond forms between the atoms?
Triple
What is an atom?
The smallest particle of an element - cannot be divided chemically.
Why are the atomic masses on the periodic table not whole number?
Because the atomic mass of an element is the average of all the isotope mass numbers of that element.
What is the difference between Bohr's model of the atom and Rutherford's?
Bohr's model has electrons orbiting the nucleus in discrete orbitals.
What is the formula of Magnesium Hydroxide?
Na(OH)2
Draw the Lewis Structure for CH2I2. Is the compound polar or nonpolar?
polar