Unit 2: chemical composition Flashcards
(67 cards)
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)
