Atomic Structure and Bonding Flashcards
How is an atom arranged?
Smallest stable unit of matter, subatomic particles arranged in a nucleus and electrons cloud.
What is rutherfords gold foil experiment findings?
The Mass of an atom and positive charge is located in the nucleus. The volume of an atom is empty space. Electrons move in circular orbits. force OF ATTRACTION between + nucleus and electrons is electrostatic.
What holds an atom together?
Electrostatic attraction; Force occurs between particles of opposite charge.
Strong nuclear force: Attractive force that occurs between all particles in nucleus, regardless of charge.
What is electron configuration and how is it determined?
Electrons from the same shell have the same energy and distance from the nucleus. Electrons with lower energy are closer to the nucleus, higher energy electrons are farther away.
Electron configuration is determined by several rules. The Aufbau principle states electrons around a nucleus fill up in order and occupy the lowest energy levels first.
What are atomic orbitals?
Regions of space around an atom. Each electron shell contains one or more sub-shells (part of an electron shell that contains orbitals) designated S, P, D, F. S has 1 orbital and can have 2 electrons, P 3 Orb and 6 Electrons. D 5 orbitals and 10 electrons. F 7 orbitals and 14 electrons. 1st sub-shell is the lowest energy and fills first.
what is The Pauli exclusion principle
States no 2 electrons can occupy the same quantum state. An orbital can hold 2 electrons they must have a different magnetic spin. (Arrows pointing up and down). Hund’s rule of maximum states every orbitation in a sub-shell will be singly occupied with one electron before orbitals became paired.
What are ground and excited states?
Ground state: Lowest energy electron configuration of an atom.
Excited state: Altered electron configuration from the ground state that occurs when an atom absorbs additional energy.
What is the electron configuration of ions?
Gaining electrons form anions that are negatively charged. Losing electrons forms cations that are positively charged. When a cation is formed electrons are lost from the highest orbital first.
What are the exceptions to the electron configuraiton of ions?
When filling orbitals, 4s is filled before 3d. Once 3d subshell is filled its energy level falls below the 4s subshell meaning when ions are formed electrons are lost from 4s before 3d.
Chromium and copper don’t follow the pattern of the other elements in period 4. Due to energy levels of the 3d orbitals changing when electrons are added.
Copper: When 3d subshell is filled its lower in energy then the 4s subshell. There will only be 1 electron in 4s. Chromium: When 3d is half filled with 1 electron in each orbital, its lower in energy and more preferential than the 4s leaving it with 1 electron.
What is chemical bonding?
Atoms do this to obtain a filled valence shell and become chemically stable. Forms due to the electrostatic force of attraction between protons and electrons. Bonds form when electrons from both atoms are attracted to both nuclei.
What is metallic bonding?
Valence electrons in metal atoms are loosely held as shown by their low ionisation energies. (Especially when heated or electrified)
Metal atoms lose electrons to form a positively charged cation. Valence electrons become attracted to the nuclei of the other atoms present and become delocalised and drawn into the space between atoms. The electro-static force between charged cations and negatively charged electrons holds the structure together.
What is ionic bonding?
Involves the transfer of electrons to form ions. Occurs between a metal and a nonmetal.
The metal loses electrons and becomes a cation.
Non-metals gain electrons and become anions.
The resulting compound will be electrically neutral.
What is the Octet rule?
8 Electrons in the valence shell. Only S and P electrons are involved not d or f shells.
The type of ion formed depends on the no. of valence electrons.
What are polyatomic ions?
2 or more atoms will together lose/gain electrons.
Ammonium = NH4^+
Hydroxide = OH^-1
Nitrate =NO3^1-
Sulfate = SO4^2-
Carbonate = CO3^2-
Phosphate = PO4 ^3-
How do you name ionic compounds and formulas?
Valency of an atom is an indication of the no. of bonds.
Write the metal first, then the non-metal change end of name to ide or ate if polyatomic. Remember the cross formula.
