Unit 2: chemical composition Flashcards
What are the 7 diatomic elements?
*Have no fear of ice cold beer
- Hydrogen (H)
- Nitrogen (N)
- Oxygen (O)
- Fluorine (F)
- Chlorine (Cl)
- Bromine (Br)
- Iodine (I)
What is matter?
Anything that has mass and occupies volume.
What’s matter that has constant propreties and composition?
A pure substance
What’s matter that doesn’t have constant properities and composition?
What are the 2 types?
A mixture!
Can either be heterogeneous or homogeneous.
What’s an element?
- Fundamental unit of matter made up of only one type of atom
- Cannot be chemically changed into a simpler substance without changing it’s properties.
All naturally occurring elements are stable and non-radioactive?
False!
Exemple, uranium and francium are unstable!
How many elements in periodic table?
118 elements and 90 naturally occuring, the rest are synthetic.
Each element is represented by a name and a symbol.
What’s atomic number, atomic weight and mass number?
- Atomic number, Z, is the number of protons in the atom’s nucleus.
- Atomic weight, mass, is the weighted average of all atoms of an element.
- Mass number, A, is the sum of protons and neutrons in atoms nucleus.
Families/groups?
- 18 vertical volumns
- Numbered 1 through 18
- All elements in a family have the same number of valence electron and similar chemical propreties
Periods?
- 7 horizontal rows
- All elements in a period have the same number of shells (couches électroniques)
3 categories in the periodic table?
1- Main group of elements (colomns 1A-2A and columns 3A-8A)
2- Transition metals (B groups 3-12)
3- Inner transition metals (lanthanides and actinides)
Common groups - Metals?
- Left side of the zigzag line (except for hydrogen)
- Solid at room temperature, conduct heat and electricity, lustrous, malleable and ductile
- Loses electrons and for cations in chemical reactions
Common groups - nonmetals?
- Right side of the zigzag line
- 11 are gases, 5 are solid and 1 liquid (Br) at room temperature
- Poor conductors of heat and electricity, non-lustrous and brittle.
- Gain electrons and form anions in chemical reactions.
Common groups - semimetals (metalloids)?
- Along the zigzag line; B, Si, Ge, As, Se, Sb and Te
- Metal properties: solid, shiny, conduct heat and conduct electricity at high temperatures
- Non metallic propreties: brittle
Groupe 1A: Alkali metals?
- Soft silvery metals
- Typically found as a compound because of reactivity (and stored in oil)
- Low melting points and boiling points
- Low densities
Groupe 2A: Alkaline Earth metals?
- Relatively soft and reactive
- Not found naturally in pure state
- Lustrous, shiny silver metals
- Relatively low melting and boiling points
Groupe 7A: Halogens
- Liquids and gases at room temperature
- Low melting and boiling points
- Not found naturally in their pure state - reactive
- Brittle when solide
- Poor conductors
Group 8A: Noble gases
- Odourless, colourless and nonreactive
- Gases at room temperature
- Low boiling points
Evolution of model of the atom?
1803: Dalton
1897: Thomson
1912: Rutherford
1913: Bohr
1930+: Schrodinger
What are the 3 particules in an atom?
1- Electrons (e-)
- Electron cloud outside of the nucleus
- Negatively charged
- Not very massive
2- Protons (p+)
- In the nucleus
- Positive charge
- Massive
3- Neutrons (n0)
- In the nucleus
- No charge
- Massive
What’s an isotope?
- Atoms with identical atomic numbers (number of protons), but different mass numbers (different number of neutrons).
What’s the octet rule?
Fill valence shell to attain a noble gas electron configuration and become stable.
2 types chemical bonds?
Covalent bonds - sharing electrons
Ionic bonds - transfer of electrons
Covalent bond?
- Sharing electrons between nonmetals
- Prefixes indicate number of atoms of each element (mono, di, tri, tetra, penta, hexa, hepta, octa, nona and deca)
- How to name? First element = full name. Second element = first part of it’s name and adding -ide + prefixes if needed. (Ex: Dinitrogen trioxide)
- Do not use the prefix mono when there is only one atom of the first element (ex: carbon monoxide)
Specific names for some compounds?
H20 = water
H2O2 = hydrogen peroxide
NH3 = ammonia
Ionic compounds?
- Transfer of electrons from one atom to another atom.
- Results in a force of attraction between charged particules.
- Metal and nonmetals.
- Don’t add prefix with ionic bonds and read from left to read!
- Ionic coumpouds are neutral, so net charge is always zero.
What is an ion?
An atom or a group of atoms that has a positive or negative charge.
Cation?
- Lost an electron
- Positively charged
- Ex: Metals
Anion?
- Gained an electron
- Negatively charged particule
- Ex: nonmetals
Type 1 ionic compound?
- Type 1: metal can only form 1 type of cation
- Cation is placed first and anion is placed second with the ending changing in -ide.
Type 2 ionic compound?
- Type 2: metal can form 2 or more cations of different charges
- Charge is specified by using Roman numerals (in parentheses) following the name of the metal.
- Name the anion like usual.
- Ex: Fe2O3 = Iron (3) oxide
Elements with multiple charges?
- Cr2+/Cr3+
- Mn2+/Mn3+
- Fe2+/Fe3+
- Co2+/Co3+
- Cu+/Cu2+
- Hg2*2+/Hg2+
- Sn2+/Sn4+
- Pb2+/Pb4+
Polyatomic ions?
Charged species containing 2 or more atoms bound together.
- Have a charge ex: +/2+/-…
- Ex: NH4+, NO3-
Atomic mass unit?
- AMU is used because the mass of an atom is very small.
- Relative to the mass of 1 atom of carbon-12
- Avergae mass of all the isotopes of an element
The Mole?
- Established to count atoms because atoms are so small
- Equals the number of carbon atoms in exactly 12.011 grams of carbon
- 1 mole = 6.022 x 10*23 atoms (avogadro’s number)
Molar mass?
Molar mass of any substance is the mass (in grams) of 1 mole of that substance.
Molecular weight?
Sum of individual atomic molar masses of the atoms that make up a compound.
Name of Hg2*2+?
Mercury
Name of NH4*+?
Ammonium
Name of NO2*-?
Nitrite
Name of NO3*-?
Nitrate
Name of SO3*2-?
Sulfite
Name of SO4*-2?
Sulfate
Name of OH*-?
Hydroxide
Name of CN-?
Cyanide
Name of PO4*3-?
Phosphate
Name of HPO4*3-?
Hydrogen phosphate
Name of H2PO4*-?
Dihydrogen phosphate
SCN-?
Thiyocyante
CO3*-2?
Carbonate
HCO3-?
Hydrogen carbonate
ClO-?
Hypochlorite
ClO2-
Chlorite
ClO3-
Chlorate
ClO4-
Perchlorate
C2H3O2-
Acetate
MnO4?
Permanganate
Cr2O7*2-?
Dichromate
CrO4*2-?
Chromate
O2*-2?
Peroxide
C2O4*2-?
Oxalate
S2O3*-2?
Thiosulfate
Molar mass?
Number of grams in 1 mol of an element
Mass number?
Number of protons and neutrons in an element
Atomic weight?
Weighted average of the isotopic masses of an element’s naturally occuring
Atomic mass?
Mass of a specific atom
Atomic number?
Quantity determined by the number of protons in an element
