Chemistry Flashcards
the study of matter, its chemical and physical properties and the chemical and physical changes it undergoes
Chemistry
a specific substance that can’t be broken down into simpler substances by chemical reactions
Element
How many elements are on the periodic table? How many are naturally occurring? How many are unstable?
118 total
94 naturally occurring
24 unstable
the arrangement of the elements that communicates important information about each of the elements and how they relate to one another
Periodic Table
What 4 things are included in each square on the periodic table?
- Atomic Number
- Chemical Symbol
- Element Name
- Atomic Mass
What does the Atomic Number represent?
protons in an atom of an element
How is the Atomic Mass calculated?
Atomic Mass = # proton + average # neutrons
How do you calculate the average number of neutrons?
Average # Neutrons = Rounded Atomic Mass - Atomic Number
the smallest component of an element that retains all of the chemical properties of that element
Atom
the central region of all atoms that contain protons + neutrons and are orbited by electrons on the outside
Nucleus
positively charged particles inside the nucleus of an atom
Protons
negatively charged particles that orbit around the outside of the nucleus of an atom
Electrons
particles with no charge inside the nucleus of an atom
Neutrons
electrons in the outer electron shell and are important for chemical reactions
Valence Electrons
Balanced atoms have what electron to proton ratio?
1:1
Atoms have the same # of electrons as protons
atoms of the same element that have the same number of protons but a different number of neutrons
Isotopes
How do you write proton vs electron charges?
Proton = +1
Electron = -1
when an atom contains an equal number of protons and electrons
Neutral Atom
Isotopes of an element are chemically _____ , BUT may have ______ stabilities
identical
different
How would you write normal magnesium (atomic mass of 24) vs an isotope of magnesium (atomic mass of 25)? And how many protons and neutrons would each have?
Mg-24
12 protons + 12 neutrons
Mg-25
12 protons + 13 neutrons
holds the atoms of two joined elements together
Chemical Bond
What part of the atom forms bonds?
Electrons
How many electrons can the first 3 orbitals hold?
First - 2
Second - 8
Third - 18
What is it called when the outer orbital is full?
Octet
How can atoms become more stable?
By filling their outermost orbital through the loss, gain or sharing of valence electrons via chemical bonds
What are the 3 main kinds of bonds?
- Ionic Bonds
- Covalent Bonds
- Hydrogen Bonds
type of bond that involves one atom losing 1 or more electrons and another atom gaining the electrons that were lost by the first atom
Ionic Bond
What does an atom become once it has a charge?
Ion
What are the 2 types of ions and what is the difference?
- Anions = ions with a negative charge
- Cations = ions with a positive charge
the result when 2 ions attract to each other and stick together to make a bond
Ionic Compound
Ionic Compounds must contain how many different elements?
At least 2
when elements share electrons to achieve a full outer shell instead of gaining or losing electrons
Covalent Bonds
How many bonds can there be in Covalent Bonds and how many electrons are involved?
Three: single, double, and triple Covalent bonds
Single Covalent Bonds - 1 electron
Double Covalent Bonds - 2 electrons
Triple Covalent Bonds - 3 electrons
the result when atoms are joined by covalent bonds
Molecule
How many different elements must Molecules contain?
Don’t have to contain different elements - can be multiple atoms of the same element
All _____ are _____, but not all ______ are _____.
(molecules/compounds)
All compounds are molecules BUT not all molecules are compounds
What are the 2 types of Covalent Bonds?
- Nonpolar
- Polar
when 2 bonded atoms share electrons nearly [equally]
Nonpolar Covalent Bond
when 2 bonded atoms share the electrons [unequally] due to a difference in charge between them
Polar Covalent Bond
Give an example of a Nonpolar Covalent Bond vs a Polar Covalent Bond?
Nonpolar - O2 (the 2 oxygen atoms are identical and thus the electrons are shared equally)
Polar - H2O (the electrons are pulled closer to the oxygen atom, thus the oxygen end of the molecule is slightly negative and the hydrogen end is slightly positive)
created when a molecule has regions of charge that are separated
Dipole
molecules with dipoles
Polar Molecules
a weak attraction between an electronegative atom in one molecule and an electropositive ____ atom already bonded to an electronegative atom in another molecule
Hydrogen Bond
How are hydrogen bonds indicated on models?
Dashed line
What is the universal solvent and why is it called that?
Water - capable of dissolving more chemicals than any other solvent
What types of molecules can water dissolve?
Polar only
Nonpolar molecules like fats and oils cannot be dissolved in water
how well molecules are attracted to themselves
Cohesion
how well molecules are attracted to other substances
Adhesion
What are 4 important properties of water that are caused by hydrogen bonding and the polarity of water?
- Universal Solvent
- Cohesion
- Adhesion
- High boiling and melting points
a substance that releases hydrogen ions (H+) and thus increases the concentration of (H+) in the solution
Acid
have an excess of hydrogen ions or hydronium ions and have a LOW pH value
Strong Acids
a substance that releases hydroxide ions (OH-) or other (-) charged ions that combine with hydrogen ions, reducing their concentration in the solution
Base
have an excess of hydroxide ions and have a HIGH pH value
Strong Base
a solution that is not acidic or basic
Neutral
a measurement scale that indicates a solution’s acidity or alkalinity on a scale from 0 to 14
pH
What is the pH formula and it can be rearranged to solve for what?
pH = -log[H+]
The Hydrogen Ion Concentration
Chemistry terms for how acidic or basic a solution is
Acidic = Acidity
Basic = Alkalinity
What is the pH inside human cells and blood?
Close to neutral
the process by which neutral atoms/molecules are converted to electrically charged atom/molecules through gaining or losing electrons
Ionization
