Chemistry - Compounds Flashcards
What is the atomic theory
- atoms are the smallest part of an element
- composed of 3 subatomic particles: protons, electrons, neutrons
- protons and neutrons make up 99.9% of an atoms mass
- electrons surround the nucleus and make up 99.9% of the volume
Do electrons closer or further from the nucleus have more energy
further, harder for the atom to hold
what are valence electrons
electrons is the outer energy level
How do you format an energy level diagram (top to bottom)
—3e— (# of electrons in each shell)
—2e—
5p (in circle) (# of protons)
6n (# of neutrons)
B (symbol of element or ion)
Are groups or periods vertical in the periodic table
groups
What are the four main groups in the periodic table
Alkali metals (group 1): soft, shiny, silver in colour, highly soluble and reactive in water.
Alkaline-earth metals (group 2): shiny and silver, but not as soft or soluble as group 1.
Halogens (group 17): poisonous and highly reactive.
Noble gases (group 18): very unreactive due to complete valance shells.
What are the three categories of elements in the periodic table
Metals are silver or grey in colour, shiny, malleable, ductile, good conductors of heat and electricity, and most are solid at room temperature; found to the left of the staircase.
Non-metals may be solid, liquid, or gas, and are poor conductors of heat and electricity; found to the right of the staircase.
Metalloids have properties that are intermediate between metals and non-metals.
What are isotopes
- Atoms of the same element that contain different amounts of neutrons, and therefore have a different mass number
- The atomic molar mass on the periodic table is an average of all of the element’s isotopes
- The most common isotope of each element is found by rounding the mass number found on the periodic table.
What is ionization
the process in which an atom gains or loses and electron to form an ion
What is a cation
positively charged ion that forms when an atom loses one or more electron
E.g. a sodium ion loses an electron giving it a 1+ charge – now called a sodium ion and written as Na+.
If the ion has more than one possible charge, indicate the charge in roman numerals after the name – e.g. Ni2+ is called a nickel(II) ion
What is an anion
negatively charged ion that forms when an atom gains one or more electrons
a chlorine atom gains one electron giving it a 1- charge – now called an chloride ion and written as Cl-.
How are ionic compounds formed
electrons transfer from one atom to another so each atom has a complete valence energy level
The cation and anion are attracted to one another by charge, forming a neutral ionic compound joined by an ionic bond.
What are multivalent elements
atoms with more that one stable ion charge, the most common is the first charge listed on the periodic table
What are Polyatomic ions
made of several non-metallic atoms joined by covalent bonds
What are the properties of ionic compounds
- might melting point and solid at room temp (attraction is strong and continuous)
- Crystalline structure
- solubility in water (each individual ion is attracted to the different end of water molecules)
- Form electrolytic solutions (dissociate into ions, the greater the concentration of ions, the greater the conductivity)
What are covalent bonds
- forms when atoms share a pair of valence electrons to make them stable
- results in the simultaneous attraction of nuclei for shared electrons
What is a molecule
an independent unit of fixed numbers of non-metallic atoms held together by covalent bonds
What are the two types of molecular elements
DO NOT EXIST AS SINGULAR ATOMS
Diatomic elements - composed of 2 atoms
Polyatomic elements - composed of many identical atoms
What is the chemical formula of ammonia
NH3(g)
What is the common name of C6H12O6(s)
glucose
What is the common name of H2O2(l)
hydrogen peroxide
What is the chemical formula for sucrose
C12H22O11(s)
what is the chemical formula of methane
CH4(g)
what is the common name of C2H6(g)
ethane
what is the common name of C3H8(g)
propane
what is the chemical formula of methanol
CH3OH(l)
what is the chemical formula of ethonal
C2H5OH(l)
what are the properties of molecular compounds
Form non-electrolytic solutions – molecular compounds do not dissociate into ions.
Low solubility – most are not soluble in water.
Relatively low melting and boiling points –tend to have weak intermolecular forces (between molecules).
Require large amounts of energy to decompose – indicates that covalent bonds (intramolecular forces) within the molecule are strong.
Molecular substances can form crystals like ionic compounds, but they crumble easily.
What makes water a polar molecule
- electrons are shared unequally
- has a slightly positive and negative side
- each end attracts other water molecules to form hydrogen bonds
What unique properties are the result of water’s polarity and hydrogen bonding
- high melting and boiling point
- ability of absorb and release lare amounts of thermal energy with small temp changes
- ice floats on liquid water
- high surface tension
- concave meniscus and capillary action - cohesive and adhesive properties
- universal solvent - pos and neg sides are attracted to other substances
How do you determine the state of molecular compounds
smaller molecules tend to be gases and larger ones are liquid or solid
How do you determine the state of ionic compounds
solid at room temp and pressure
How do you determine the state of ionic compounds in an aqueous solution
USE CHART THINGY
If the compound is very soluble then the state is aqueous.
If the compound is only slightly soluble then the state is solid.
what does pH measure
concentration of hydrogen atoms in a solution
lower the number the more acidic and higher number is basic
What are acid-base indicators
chemicals that change colour depending on the pH of the solution – e.g. litmus paper, phenolphthalein.
What are the properties of acids
- sour
- reacts to metals to produce hydrogen gas
- pH under 7
- conducts electricity
- red litmus
- neutralized by bases
What are the properties of bases
- bitter
- slippery
- pH over 7
- conducts electricity
- blue litmus
- neutralized by acids
How do you recognize an acid
- look for hydrogen symbol on the left or COOH on the right
- ionize in water to release hydrogen ions
- compounds only become acidic when in an aqueous environment
What are the naming rules for acids
hydrogen ________ide. –> hydro_________ic acid
eg. hydrogen chloride. hydrochloric acid HCl(aq)
HCl(g)
hydrogen ________ate.–> _____________ic acid
eg. hydrogen chlorate. chloric acid HClO3(aq)
HClO3(s)
hydrogen ________ite. –>. _____________ous acid
eg. hydrogen chlorite. chlorous acid HClO2(aq)
HClO2(s)
How do you recognize a base
hydroxide OH
