Bio chapter 2
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The smallest fundamental unit that retains the properties of the element or compound.
One type of atom.
The number of protons in the nucleus of an atom. This number is given on the periodic table, above abbreviation symbol.
Atoms are composed of 3 fundamental particles. Name the particle, it's charge and location.
- 1. Proton, positive charge, located in the nucleus.
- 2. Neutron, neutral charge, located in the nucleus.
- 3. Electron, negative charge, located orbiting the nucleus.
The central part of the atom that houses the protons & neutrons.
The clouds surrounding the nucleus where the electrons exist.
What do electrons do?
Electrons are involved in all chemical reactions. They give an atom ormolecule it's unique chemical properties.
How do you find the Atomic Mass?
The atomic mass (A) is equal to the number of protons (Z) plus the number neutrons. The atomic mass (Z) number is written on the top left side of the symbol.
The atomic number is found on the periodic table above the symbol. It is equal to the number of protons. It is written on the bottom left side of the symbol.
How do you find the number of neutrons in an atomic symbol?
You subtract the atomic number from the atomic mass. N = A - Z
Atoms with the same number of protons but a different number of neutrons.
Certain isotopes are unstable & will spontaneously break down to form a more stable nucleus.
Atoms are electronically neutral unless the number of electrons does not equal the number of protons.
A type of force that holds 2 or more atoms together.
An electron is taken from one atom by another atom. "electron stealing"
Ionic Bond = metal + non metal
ElectronsElectrons are shared between atoms. "electron sharing"
Covalent Bond = non metal + non metal
A measure of how strongly an atom holds on to it's electrons.
Polar Covalent Bond
If 2 atoms in a covalent bond have significantly different electronegativity values, than a polar covalent bond is formed. (the difference should be between 0.5 to 1.7)
Hydrogen bonds form when a hydrogen atom is directly bonded to an atone of nitrogen, oxygen or fluorine. Hydrogen bonds are a specific type of strong polar bonds.
van der Waals forces
A weak type of attraction between molecules. This occurs when the covalent bonds of a molecule have a electronegativity difference of less than 0.5 A hydrocarbon is a van der Waals force.
Heat storage / Heat capacity
Water conducts heat more effectively than air. (approx. 6 times more effectively)
As a solid, water is less dense than as a liquid. (ie: ice floats)
High heat of vaporization / High boiling point
Everyframe of water that evaporates from human skin takes heat away from the body, this is why we sweat when we are physically active.
Because of the abundant hydrogen bonding, water molecules stick together and at the surface of a body of water the molecules form a "skin". Cohesion occurs when molecules are attracted to other molecules of the same type.
Occurs when polar molecules are attracted to different polar molecules.
Water is sometimes called the universal solvent because many substances will dissolve in it. Because water has a polar covalent bond, it will dissolve other molecules that also have a polar covalent bond.
Water-loving. Will dissolve in water. Polar covalent bonds and hydrogen bonds are hydrophilic.
Water + fear. Repels water. Will not dissolve in water. Van der Waals forces are hydrophobic.
Adding an acid to water will increase the number of H3O+ ions present. Acid has a pH below 7.
Adding a base to water will increase the number of OH- ions present. The pH of a base is higher than 7.
Solutions that are made to resist changes in pH.
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