Day 1 Flashcards
What is an atom
Building block
What is an element
Collection of like atoms. Examples: Carbon, hydrogen, gold.
What is a molecule?
Covalently bonded atoms (units of chemicals). Examples include H2O, CH4 (methane), NH3 (Ammonia) but also O2 and H2.
What is a compound?
Compositions of different atoms. There are two types: molecular (covalently bonded “clumps” of molecules) or ionic (ionically bonded “latices”). Examples include H2O, CH4 (methane), NH3 (Ammonia).
Atomic weight
The resulting mass from taking the weighted average for the different existing isotopes for that atom type (note this is a mass, not a weight). (The number given by the periodic table)
Atomic mass
Total mass of protons and neutrons of a given element.
Atomic number
The number of protons in an atom.
Isotope
One of two or more variations of a given element differentiated by the number of neutrons. Think siblings. Examples: carbon-12, carbon-14.
Nucleon
Neutron or proton
Mole
Unit of measurement. 1 mole of any element contains avagadro’s number of constituent components. So 1 mole of carbon contains 6.022 x 10^23 atoms of carbon. 6hundred and 2 hexazillion.
Ion
An atom or molecule with non-zero net charge. This comes from having a different number of protons and electrons.
Reactant
An input in a chemical reaction.
Product
An output in a chemical reaction.
Significance of a mole.
Avagadro’s number is a nice way to convert to a standard measures of mass. This is because it is pretty much based off how many AMUs are in 1 gram. An AMU is pretty much the weight of a nucleon. So there is 1g of mass per mol of AMU.
Elementary particles
The most basic units of matter. The types are leptons, quarks, and force carriers (photons are one). These compose hadrons such as protons and neutrons. Electrons are an elementary particle (lepton).
Molarity
Molar concentration of a chemical species in a solution expressed as mols per liter.
Mass number
The total number of nucleons.
Cation
A positively charged ion.
Nucleus
Positively charged center of atom consisting of protons and neutrons.
Exothermic
Reaction that releases heat.
Endothermic
Reaction that consumes heat.
Relative abundance
The fraction of a single isotope that exists on earth. Determined by mass spectrometry (how does it generalize from the sample to the population?).
Dalton’s Atomic Theory
1: All matter is made of atoms, which are indivisible.
2: All atoms of a given element are identical in mass and properties.
3: Compounds are combinations of two or more different types of atoms.
4: A chemical reaction is a rearrangement of atoms.
Law of conservation of mass
Matter is neither created nor destroyed in a closed system - used in chemical equations.
Law of constant composition
A pure compound will always have the same proportion of the same elements. So salt (NaCl) contains the same proportions of the elements sodium and chlorine no matter how much salt you have or where the salt came from.
Covalent bond
Bond created by the sharing of electrons. Happens between non-metals. One atom gives the other atom an electron while taking an electron. Each atom needs to “want” an electron.
Ionic bonds
Bonds based on ionic atoms attracting. Happens between metal with non-metal based compounds.
Anion
Negatively charged ion.
Example for how fast the speed of light is
It takes 2.5 seconds for radar waves to leave earth, bounce off the moon, and return - a total of 478k miles.
Refraction
The deflection of something as it goes crosses the boundary into a new medium.
Diffraction
The spreading of waves after passing through a small opening.
-ide suffix
Signifies an anion.
In a chemical structure drawing, what do brackets represent?
Ionic bond
In a chemical structure drawing, what do connecting lines represent?
Shared electrons
Formula unit
The unit of an ionic compound structure (almost never exists alone in nature). Similar to the idea of a molecule for covalent bounds.
Example of how large the avagadro’s number is
A mole of jellybeans would be as big as the earth.
What are diatomic elements?
Elements where the atoms pair if they are alone (i.e., there aren’t other elements that could potentially create different compounds).
Molar mass
The mass of one mole of the element.
What is the basis for all chemical bonding
Electrostatic attraction.
What is the general rule that predicts how a given element will be ionized?
How they can get a full valence ring (either by gaining or loosing electrons).
What is a period w.r.t. the periodic table? What is the significance?
A row. The row number corresponds to the number of electron shells / energy levels.
Polyvalent
Elements that occur in various ions (have varying charges).
Polyatomic ion
An ion composed of multiple atoms.
Molar ratio
The ratios of a reaction determined by stoichometry.
Molecular mass
The mass of the molecular (in amu).
Polar bonds (and how it’s shown)
One of two types of covalent bonds. This is where the covalent bond, due to one atom “pulling” the electrons with a greater force than the other, starts to become closer to an ionic bond. Due to this asymmetry, there is a polarization. A polar bond is shown with a delta and a ‘+’ or ‘-‘ next to the atoms to indicate the polarity.
An example is H2O.
Hydrogen bond
One of two types of covalent bonds. This is where a polar bond creates a two polarized atoms in a molecule, one positive and one negative. This molecule then forms ionic-like bonds with other similar molecules. The resulting bond between the molecules is called a hydrogen bond. Seems to be called a “hydrogen” bond because it: always occurs with hydrogen because hydrogen has the unique property of having a single electron which, one involved in one bond, leaves the proton “unshielded” giving it strength to interact with other molecules.
Metallic bonds
- Electron Sea
* Transition metals with
volatility
In chemistry and physics, volatility is quantified by the tendency of a substance to vaporize
Dotted lines in chemical bonding model
Hydrogen bond.
Ionization energy
The amount of energy required to pull an electron away. Quantified by coulumb’s law (attraction force between charges).
