TEST 1 KEY TERMS Flashcards
Metals & their properties
form cations in solutions or ionic compounds and produce basic oxides.
typically lustrous, hard, have high density, high tensile strength, are ductile, malleable, high melting / boiling points, good conductors of heat and electricity
Non-metals & their properties
form anions in solutions or ionic compounds and produce acidic oxides.
generally dull, poor conductors of heat and electricity, have high ionization energies and electronegativity, are neither malleable nor ductile (often brittle), and have lower density, melting points, and boiling points compared to metals
Metalloids
Elements exhibiting intermediate properties between metals and non-metals.
Periodic table GROUPS
(Columns): Each group indicates the number of valence (outer shell) electrons. Elements within the same group share similar chemical properties.
Periodic table PERIODS
(Rows): Each period signifies the number of electron shells an atom possesses. As you move across a period, the number of valence electrons increases by one in each column.
Periodic table trends
Atomic radius: decreases right, increases down
Reactivity with water: decreases right, increases down
Metallic characters: decreases right, increases down
Ionisation energy: increases right, decreases down
Electron affinity (electronegativity): increases right, decreases down
Melting/boiling points: increases towards centre (cobalt/nickel), decreases down
Chemical bonding
Lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds.
All chemical bonding is an electrostatic force of attraction
Types of INTRAmolecular forces
Metallic bonding, ionic bonding, covalent bonding
Metallic bonding
The collective sharing of a sea of valence electrons between several positively charged metal ions
Properties
attributed by metallic
bonding
- Electrical Conductivity
- Thermal Conductivity
- Malleability and Ductility
- Metallic Luster
- High Melting and Boiling Points
Ionic bond
Chemical bond formed between a metal and nonmetal atoms through the transfer of one or more electrons. Crystalline structure
Metal becomes a cation, the nonmetal becomes an anion
Properties of ionic bonds (compounds)
- Form crystals
- High melting and boiling points
- Hard and brittle
- Conduct electricity when they are dissolved in water
- Good insulators
Electrovalency
Number of atoms lost by one atom or gained by the other atom
Covalent bond
Sharing of electron pairs between two non-metal atoms with the same or close electronegativity
How are covalent bonds divided
Nonpolar covalent bond (less than 0.5 electronegativity)
Polar covalent bond (0.5-1.9 electronegativity)
Greater than 1.9 = ions formed
Number of shared pairs and the bonds they form
- One shared pair forms a single bond
- Two shared pairs form a double bond
- Three shared pairs form a triple bond
INTRAmolecular forces
Chemical bonds that hold atoms together WITHIN a molecule, forces which determine chemical properties
INTERmolecular forces
Attractive (between protons) or repulsive (between electrons) forces that exist BETWEEN molecules, forces which influence physical properties
What properties do inter/intramolecular forces determine
inter = physical (and some chemical) properties
intra = chemical properties
Types of INTERmolecular forces
- Dipole-Dipole Interactions
- Hydrogen bonds
- Dispersion Forces
Dipole-dipole interactions
Attractive forces between polar molecules, where the positive end of one molecule is attracted to the negative end of another.
Affects properties like boiling and melting points
Hydrogen bonding
Type of dipole-dipole interaction but seperate due to strong nature. (strongest of inter forces)
Forces of attraction between molecules containing fluorine (F), oxygen (O) or nitrogen (N) bonded to hydrogen.
F-H
O-H
F-H
Results from large elcetronegativity different and small atomic size of hydrogen
Strengths of the different intermolecular forces
Strongest: hydrogen bond
Medium: Dipole-dipole interactions
Weakest: Dispersion forces (Van der Waals)
Dispersion forces (Van der Waals)
Caused by temporary shifts in electron distribution, creating instantaneous dipoles that attract neighboring molecules.
ALWAYS PRESENT (but may just break/disperse upon increase in distance between) - but you can never just have dispersion forces
