Unit 9 Flashcards
Ammonium ion
NH4 ( small 4 )
Carbonate ion
CO2- ( up) and 3 down
Hydroxide ion
OH -1 (up)
Nitrite ion
NO -1 (up) and 2 ( down )
Nitrate ion
NO -1 (up) and 3 down
Sulphate ion
SO -2 ( up) and 4 down
Sulphite ion
SO -2 (up) and 3 down
Hydrogen carbonate ion
HCO -1 (up) and 3 down
What is Nicotine
C10H14N2 is a naturally occurring alkaloid compound from the nightshade family of plants. Used as a stimulant and anxiolytic .
What is valency
Valency refers to the number of electrons an atom has to lose or gain to have a full outer shell ( combining power )
Where are electrons found
In shells orbiting teh nucleus of teh atom
What does the location of an element on the periodic table tell us ?
Groups numbers show valency and periods show number of shells
Electron configuration
Representation of arrangement of electrons among the orbital shells and sub shells
What are teh three types of bonds
- Covalent bonds
- Ionic bonds
- Metallic bonds
Ionic bonding ( 4 )
• occurs between metal and non-metal atoms.
• Electrons are transferred between atoms
• This produces ions (charged atoms)
Forms metal compounds
Properties of ionic compounds
- high melting and boiling points
- forms giant crystalline lattice structures
- Ionic compounds can conduct electricity if dissolved or molten
Covalent bonding ( 3 notes )
● Non - metal atoms like to covalently bond
● Sharingofelectronswithinachemicalbond
● Toobtainafulloutershellofelectrons
What happens in an ionic bond ( 2 )
In ionic bonds the metals lose electrons ( t become a positively charged cation ) and the non metals accepts these electrons to became a negatively charged anion.
What is an ionic bond
Electrostatic force of attraction between a positive metal and a negative non metal ( between oppositely charged ions )
Lattice energy
Energy required to convert one mole of an ionic solid into its gaseous ionic constituents
What is lattice enthalpy and what does it depend on
- Lattice enthalpy is teh measure of strength of forges between teh ions in an ionic compound.
- depends on ionic radius and charges of ions
What is electricity
Flow of electrons ( slat does not conduct electricity in its solid state )
Why do ionic compounds have high melting and boiling points (3)
This so because ionic compounds are held together by strong electrostatic forces between oppositely charged ions. These forces are known as ionic bonds. Because the ionic bond ( lattice ) contains so many ions a large amount of energy is needed to overcome these bonds,
Electrical condictivulty property of ionic compounds explanation
When molten or aquas teh ions are free to move around, mobile charged particles are needed to conduct electricity. The solid lattice does not allow ions to move from tehir fixed positions. In liquids this sold lattice is broken and ions can move free,y and therefore conduct electricity.
What causes ionic crystals to shatter
If the crystalline structure was places under stress, like being hit by a hammer, this could result in a shit in Teh planes of ions. I’d ions of teh same charge came into contact, teh repulsive forces would cause the crystal to shatter
Why are some ionic compounds less soluble
When teh charges are greater or ions are in closer proximity. The bonds between teh ions are stringer, so teh ions are less attracted to the polar water molecules. As a result tehy are less soluble
What does teh molecular formula of a compound describe ?
The actual number of individual atoms in a molecule of teh compound
Metallic bonds result from ?
Electrostatic attraction between a lattice of positive ions and the delocalized electrons. The attraction between delocalised electrons and the positive ions in a regular lattice.
What are delocalized electrons
Electrons that are free to move throughout a whole structure
What are ions and how are they formed and why are they charged ?
An ion is a charged particle. They are formed when atoms gain or lose electrons to form a full outer shell. Ions are charged because the number of protons is different from the number of electrons.
When are covalent bonds formed and what do they occur between
A covalent bond is formed when two atoms share electrons to obtain a noble gas configuration. Covalent bonding occurs between non-metal atoms.
are ionic or covalent bonds stronger
Generally, ionic bonds are much stronger than covalent bonds. In ionic bonds, there is complete transfer of electrons between elements to form a stable compound. While in covalent bond, there is only sharing of electrons between two elements to form a stable compound.
Two types of structures formed by covalent bonding
molecular covalent structures. Simple molecules held together by weak forces of attraction. Examples include iodine, methane and carbon dioxide.
giant covalent structures. Many atoms joined together by strong covalent bonds. Large and variable number of atoms. Examples include diamond and graphite.
van der Waals’ (3)
Intermolecular attractions found between molecules of substances . Distance dependent, do not result form a chemical electronic bond. Relatively weak when compared to ionic and covalent bonds . Two types exist : London dispersion forces and dipole-dipole forces
Electron charge density
The chance that an electron of an atom is in a certain area in the electron cloud at a specific time is called the “electron charge density.
Polarizability
The ability of a molecule to become polar and displace its electrons is known as the molecule’s “polarizability.”
Physical properties of molecular covalent structures (not giant )- 3
- low melting and boiling points ( Little energy is needed to break the weak van der Waals’ forces between the molecules )
- do not conduct electricity or heat. Covalent molecular structures do not conduct electricity because the molecules are neutral and there are no charged particles
-insoluble in water. Most covalent compounds are insoluble in water. Hydrogen chloride and ammonia are exceptions, because they react with water.
Allotropes
Allotropes are different forms of the same element, in the same state. Graphite,graphene and diamond are allotropes of the same element (carbon) in the same state (solid).
The carbon atoms in a diamond form a ?
The carbon atoms in a diamond form a regular tetrahedral structure.
What are teh three main types of metal lattice structures ?
Face-centered cubic ( FCC ), body-centered cubic ( BCC ) and hexagonal close packed ( HCP )
How are the valance electrons placed in ionic bonding
Ionic bonding is the complete transfer of valence electron(s) between atoms.
What does ionization energy mean ?
Energy required to remove an electron from the outer electron shells.