Ch2 Atoms, Molecules & Ions Flashcards
Law of constant composition
each compound has the same kind and number of elements
Low of conservation of mass
in chem RXN, the total mass before is equal after rxn.
Law of multiple proportions
mass of B combined with A = ratio of small whole numbers
when A & B make more than 1 compound
Atoms are electrically…
Neutral
or protons =
of electrons
Ion
charged atom/ group of atoms
Ionic Bonds
electrical attraction amongst charged ions (strong bond)
P. Table group 1
Alkali metal (1+ charge)
Group 2
Alkaline earth metals (2+ charge)
Group 3
3+ charge for Al & B only
Group 6
Oxygen family 2- charge Oxide/ sulphide
Group 7
Halogens (1- charge) drop ‘ine’ and add’ ide’
Group 8
Noble Gases - full valence shell and No Ionic formation
Covalent Bonding
electron sharing (weaker attraction) - organic substances like wood, skin / hair
Metalic Bonds
Share AND transfer of electrons
- STRONGEST BOND (Metals & alloys)
Model of Atom
- positive charge in center, e- in orbit
- p+ & N in nucleus = atomic mass
- e- are responsible for atoms volume
Angstrom
non- SI unit to denote atomic length
1/10 of a Nanometer
Atomic Number
no. of p+ in nucleus
Mass Number
No. of p+ and N in nucleus
- Isotopes have same p+ but different mass # due to more neutrons
Isotope
different number of neutrons
Atomic mass units
Used to measure small masses of individual atoms
Rows in periodic table —>
Periods
Columns
Groups
Metals location on P. Table
Left side
good conductors/ malleable / lustrous
Nonmetals location
top right side
brittle/ dull / poor conductors
Molecule structure
2+ atoms bound tightly together
Molecule chemical formula
which atoms are present, and in what proportions (h2o)
Emperical formulasn
give relative number and types of atoms in molecule (ratio considered)
Positively charged Ion
Cations (metals in general)
Negatively charged Ions
Anions ((generally nonmetals)
