Honors - Unit 1 - Atomic Structure Flashcards
When is a photon emitted from an atom?
A photon is emitted as an excited electron returns to its ground state.
Proton
Positively charged subatomic particle. Contained inside the nucleus. Neutrons and Protons weigh roughly the same (1 atomic mass unit).
Nucleus
The center of an atom. Contains the protons and neutrons. Since neutrons have no charge and protons are positively charged, the nucleus has an overall positive charge.
Neutrons
Neutrally charged subatomic particle. (No charge) Contained inside the nucleus. Neutrons and Protons weigh roughly the same (1 atomic mass unit)
Electrons
Negatively charged subatomic particles. Electrons can be found in the space around the nucleus. This area is often called the electron cloud. Electrons have NO mass.
Atomic Number
Identifies an element. The number of protons. For a neutral atom, the number of electrons will equal the number of protons. For an ion (charged atom) the number of electrons will not be the same as the atomic number.
Atomic Mass Number
Also known as the Mass Number or Atomic Mass.
How to calculate neutrons:
of Neutrons = Atomic Mass Number - Atomic Number
Isotopes
Atoms of the same element which have a different Mass Number due to a differing number of neutrons.
The symbol for an Isotope is the element symbol followed by the Mass Number, for example:
Na-23 and Na-24
Ions
Atoms or groups of atoms with a charge. To have a charge an atom must have gained or lost electrons. If an atom gains electrons it becomes negatively charged. If an atom loses electrons it will become positively charged.
Cations
Positively Charged Ions. In general, cations are metals.
Anion
Negatively charged Ions. Anions are negatively charged because they have gained an electron(s) (electrons are negative). In general, anions are nonmetals.
Period
Horizontal row on the periodic table.
Group or Family
Vertical Column on the periodic table. Elements in the same family have similar properties.
Electron Configuration
A shorthand method of writing the location of electrons by sublevels.
Photon
Energy given off in the form of light by an excited electron. Otherwise known as a “quanta of light”.
Sublevel
Principal energy levels are broken down into sublevels designated s, p, d, or f upon which electrons travel.
Orbital
Sublevels can be broken down into regions called “orbitals”. An orbital is defined as the most probable location for finding an electron. Each orbital holds 2 electrons.
Orbital Diagram
Shorthand method of writing the location of electrons by orbital.
Pauli Exclusion Principle
If there are two electrons in an orbital, they must have opposite (paired) spins.
Hund’s Rule
When filling sublevels other than s, electrons are placed in individual orbitals before they are paired up.
Electrons fill like people do on a bus. You would never sit right next to someone you do not know if there are free seats available, unless of course all the seats are taken then you must pair up.
So, when working with the p sublevel, electrons fill like this…up, up, up….down, down, down…
Quantum of Energy
Absorbed when an electron moves from its ground state to its excited state.
Valence Electrons
Electrons found on the outer energy level. Represented by Roman Numerals. Transition Elements do not have Roman Numerals which denote their valence electrons.
Roman Numerals
Above groups/families Roman Numerals represent the number of valence electrons.
When writing the name of an ionic compound which includes a transition metal a Roman Numeral is used to denote the quantity of positive charge associated with that transition metal.
What element is represented by this orbital diagram?
Carbon
What is the orbital diagram for Magnesium?
What is the orbital diagram for Sulfur?
What is the orbital diagram for Oxygen?
What is the orbital diagram for Nitrogen?
What is the orbital diagram for Silicon?
What element is represented by the following orbital diagram?
Fluorine
What is wrong with the following orbital diagram?
This diagram does not follow Hund’s Rule. Electrons must fill energy levels from lowest to highest.
Electronegativity
Tendency of an atom to attract electrons to itself when it combines with another element.
Electronegativity increases from left to right across a period on the periodic table.
Electronegativity decreases as you go down a group on the periodic table.
What at problems where there with the Rutherford model of the atom?
Describe the Bohr Model of an atom.
What are the four Quantum Numbers? What do they stand for?
Atomic Size
Size of an atom.
Depends on the number of energy levels and the overall charge of the nucleus (the nucleus’s charge depends on the number of protons).
As you go down a group you are adding energy levels (rings around the nucleus) so the atomic size increases.
As you go across a period the atomic size decreases because the energy levels (which contain negative electrons) are increasingly attracted to the positive protons in the nucleus of the atom.
Electronegativity
Tendency of an atom to attract electrons to itself when it combines with another element.
Electronegativity increases from left to right across a period on the periodic table.
Electronegativiy decreases as you go down a group on the periodic table.
Draw an isotope of Oxygen.
Your answer should have a different # of neutrons than the Periodic Table.
Draw an ion of flourine.
You need to have 1 extra electron than normal.
What sublevels are in the fifth energy level? The third?
How many total electrons are in the third energy level? The fifth?
Sublevels: Fifth energy level s, p, d, & f. Third energy level s, p, & d.
Total electrons: 18 in the third….32 in the fifth
(count the boxes across that row)
