Q1: how do chemicals relate to biology?
A1: Biology is a multidiscplinary science. And chemistry is applied to solve nature problems.
Q2: what are some important matters we should know in chemistry?
A2: compounds, atoms, molecules, and chemical bonds,etc.
Q3: what does make matter?
A3: elements
Five facts:
1. matter is made up of elements; atom is unit of an element; compound contains two or more elements.
2. atom conclude electrons, protons, and neutrons.
3. orbitals: 1s 2s 2p
4. covalent bonds share electrons; electrons transfer in ionic bonds
5. chemical reactions change reactants into products.
Figure
A1: Biology is a multidiscplinary science. And chemistry is applied to solve nature problems.
Q2: what are some important matters we should know in chemistry?
A2: compounds, atoms, molecules, and chemical bonds,etc.
Q3: what does make matter?
A3: elements
Five facts:
1. matter is made up of elements; atom is unit of an element; compound contains two or more elements.
2. atom conclude electrons, protons, and neutrons.
3. orbitals: 1s 2s 2p
4. covalent bonds share electrons; electrons transfer in ionic bonds
5. chemical reactions change reactants into products.
Figure
The valence shell of chlorine has 7 electrons. So it needs one more electron from sodium to keep balance. As a result, chlorine and sodium can bond together as ionic bond.
Summary:
Organisms are composed of matter; matter is made up of elements. Carbon, oxygen, hydrogen, and nitrogen make up 96% of living matter. Trace elements are needed rarely by organism. Atomic number is the number of protons; mass number is the sum of protons and neutrons. Isotopes are same element atoms have different neutrons. Potential energy is caused by location and structure. Electrons are founded in different electron shells. The farthest shell is valence shell.
Chemical bond is stoms staying close together. Single bond shares a pair of electrons; double bond shares two. The same atoms are equally electronegative, and the bond is nonpolar covalent bond. Ion is charged atom: cation is positive, anion is nagative. Molecules sharpded as tetrahedron. If the rates of the forward and reverse reactions are equal, the reaction reaches equilibrium.
key terms:
- atomic mass-The total mass of an atom, which is the mass in grams of 1 mole of the atom.
- atomic number-The number of protons in the nucleus of an atom, unique for each element and designated by a subscript to the left of the elemental symbol.
- chemical bond-An attraction between two atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells.
- chemical equilibrium-In a chemical reaction, the state in which the rate of the forward reaction equals the rate of the reverse reaction, so that the relative concentrations of the reactants and products do not change with time.
- covalent bond- A type of strong chemical bond in which two atoms share one or more pairs of valence electrons.
- electronegativity-The attraction of a given atom for the electrons of a covalent bond
- hydrogen bond-A type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule.
- ionic bond-A chemical bond resulting from the attraction between oppositely charged ions.
- isotope- One of several atomic forms of an element, each with the same number of protons but a different number of neutrons, thus differing in atomic mass.
- van der Waals interactions-Weak attractions between molecules or parts of molecules that result from localized charge fluctuations.
Video:
http://www.youtube.com/watch?v=2mzDwgyk6QM&feature=related
sodium chloride
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