Day 2 Flashcards
Synthesis reactions
A reaction where the reactants combine to make a whole. A + B -> AB
Decomposition reaction
A reaction where a whole is broken down to parts (which could still be compounds or molecules). AB -> A + B
Combustion reaction
Combustion usually occurs when a hydrocarbon reacts with oxygen to produce carbon dioxide and water. In the more general sense, combustion involves a reaction between any combustible material and an oxidizer to form an oxidized product. CxHy(Oz) + O2 -> CO2 + H2O
Oxidizer
An oxidizer is a type of chemical which a fuel requires to burn. Most types of burning on Earth use oxygen, which is prevalent in the atmosphere. An oxidizer works by stealing electrons (so it should have a high electron affinity).
Electronegativity and how it trends on the PT.
A measure of the tendency of an atom to attract a bonding pair of electrons. As you move down a group on the periodic table, the electronegativity of an element decreases because the increased number of energy levels puts the outer electrons very far away from the pull of the nucleus. Electronegativity increases as you move from left to right across a period on the periodic table since the number of protons are increasing. See https://study.com/academy/lesson/electronegativity-trends-among-groups-and-periods-of-the-periodic-table.html.
Top 5 elements in the universe (expected).
- Hydrogen (1)
- Helium (2)
- Oxygen (8)
- Carbon (6)
- Neon (10)
Nuclide
A species of atom differentiated by its number of protons (Z), neutrons (N), and energy state. Similar to the concept of isotopes but the emphasize is on differences affecting the nuclear rather than chemical properties.
Ionization energy
The energy required to remove an electron from a neutral atom.
Electron affinity
The energy change when a neutral atom attracts an electron to become a negative ion.
Oxidize
The process of taking an electron from an element.
Single replacement (displacement) reaction
An element replaces another element in a compound. The analogy is dancing couples. A + BC -> B + AC
Double replacement (displacement) reaction
The positive and negative ions of two compound switch places. AB + CD -> AD + CB
Limiting reagent
(Or limiting reactant or limiting agent). The first reactant to be used up in a reaction. It limits a given chemical reaction due to its scarcity and is therefore the limiting factor in the continuation of the reaction.
Excess reagent
The reactant that exists in excess in a given chemical reaction and is therefore not the limiting factor in the continuation of the reaction.
Bohr model
A model of the atom that is analogous to orbiting planets. It is less accurate than the quantum mechanical model but still useful in many contexts.
Quantum mechanical model
A model of the atom that describes the movement of electrons around the atom as non-circular “orbitals”.
What is an electron shell?
It is a “shell” around the nucleus where electrons probabilistically reside. Electrons in a given shell have a certain energy level.
Atomic orbital
The wave function for an electron in an atom (different from orbital).
Wave function
A function that, when squared, gives the probability of finding a certain particle within a given region of space.
Principle quantum number
n - gives the energy level of an electron (aka, shell). Integers from 1 to infinity. Also sometimes labeled as K, L, M, N, …
Angular momentum quantum number
l - gives the shape of the orbital. Is an integer from 0 - n-1. Orbitals of the same n but different l are said to be in different subshells. Integers can be written as s, p, d, f, g
Magnetic quantum number
ml - the orientation of the subshell. There are always 2l + 1 orbitals for each subshell, differentiated by m.
Spin quantum number
ms - the electron spin (as it orbits). Can be +1/2 or -1/2.
Oxide
An oxide is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. “Oxide” itself is the dianion of oxygen, an O2– atom. Metal oxides thus typically contain an anion of oxygen in the oxidation state of −2.
Pyrophoric
A substance that ignites spontaneously in air at or below 55 °C (130 °F). Examples are iron sulfide and many reactive metals including plutonium and uranium, when powdered or thinly sliced. The creation of sparks from metals is based on the pyrophoricity of small metal particles, and pyrophoric alloys are made for this purpose.[2] This has certain uses: the sparking mechanisms in lighters and various toys, using ferrocerium; starting fires without matches, using a firesteel; the flintlock mechanism in firearms; and spark-testing ferrous metals.
Core electrons
Electrons inside of the valence shell.
Mneumic for angular momental quantum number
Scientists, Please! Don’t Forgo Gazing at Heisenberg’s Ill Kicks!.
