The Chemical basis of Life

Anything that occupies ___________ and has _________.

◦ Mass is commonly measured by how much something weighs

◦ Can exist as: ____________ ____________ ____________

Element- The simplest form of matter that cannot be broken into smaller substances by natural means.

◦Hydrogen, Oxygen, Carbon, and Nitrogen make up 96% of the matter in an animal’s body.

◦Elements are referred to by a ____________ ______________and are organized in the Periodic Table of Elements.

GROUP

PE

RIO

D

Major Elements◦ Oxygen(O)◦ Carbon(C)◦ Hydrogen (H)◦ Nitrogen (N)

Minor Elements◦ Calcium (Ca)◦ Phosphorus(P)◦ Potassium(K)◦ Sulfur(S)◦ Sodium(Na)◦ Chlorine (Cl)◦ Magnesium (Mg)

◦ Silicone (Si)◦ Aluminum (Al)◦ Iron (Fe)*◦ Manganese (Mn)◦ Fluorine (F)◦ Vanadium (V)◦ Chromium (Cr)◦ Copper (Cu)*◦ Boron (B)◦ Cobalt (Co)◦ Zinc (Zn)*◦ Selenium (Se)◦ Molybdenum (Mo)◦ Tin (Sn)◦ Iodine (I)*

The ___________ unit of an element that retains the unique properties of that element.

Composed of 3 subatomic particles:◦ _________________◦ _________________◦ _________________

Protons and Neutrons are found in the __________________.

Each proton and neutron has an atomic mass of ~1.◦ Together protons and neutrons determine the

atomic ____________ of the atom.◦ The atomic _____________ of an element is

equal to the number of protons in that element.

Protons have a ______________charge.

Neutrons have __________ charge and are considered neutral.

Electrons have a ________________ charge.

Net charge of atoms are neutral because have equal numbers of protons and electrons.

Tiny particles that remain in constant motion around the ________________.

So tiny that their mass does not contribute to the atomic _____________ of the atom.

Electrons have a ____________charge.

The atomic number of an atom tells us how many ______________ it has. This number cannot change as it is what makes each element unique.

If an atom loses or gains an ______________ in an attempt to fill its outermost electron shell then it becomes positively or negatively charged, thereby becoming an __________.

If an atom has a different number of neutrons, they are called ________________ of the element

e-

Na atom11electrons, 11protons

Na+ ion10electrons, 11protons

“Pathways” around the nucleus where electrons orbit◦ There are one or more shells

surrounding the nucleus, depending on the # of electrons.

◦ An electron’s energy level determines which shell it will inhabit.

◦ Lower energy electrons exist in the 1st electron shell (closest to the nucleus)

◦ Higher energy electrons are in the 2nd shell

◦ Only a certain number of electrons can be on each pathway/shell

◦ First shell can contain two electrons.

◦ Second shell can contain eight electrons.

If the outermost shell is not full, then an atom will be more active in an attempt to fill it.

Helium and Neon have full electron shells so are considered chemically inactive/inert.

Atoms are most stable when their shells are full.

Atoms with incomplete shells are constantly trying to find electrons to complete their outer shell.

___________________- form when two or more atoms are joined together by chemical bonds.

Molecule of the __________________-two or more atoms of the same element are joined together. Example: Oxygen, O2

________________ -two or more atoms from different elements are joined together. NaCl, CO2

Chemical bonding means that atoms are _________________ or __________________ electrons.◦ By doing this, each atom can be sure that its outermost

shell is full.

Atoms are constantly trying to become more stable.

Types of chemical bonds:◦ _________________, _________________, _________________

Bonds formed when atoms ______________ electrons.

Classified depending on how many electrons are being shared.

◦ single covalent bond: ______ electron is shared

◦ double covalent bond: ______ electrons are shared

◦ triple covalent bond: ______ electrons are shared

The shared electrons spend part of their time in the electron shell of each of the atoms.

Shared electrons in a covalently bonded molecule may spend more time near one atom than the other

Shared electrons in water molecule spend more time near the __________atom than __________ atoms

◦ Poles are created Gives molecule a slight _________ charge on H side of

molecule and slight _________charge on O side of molecule

Formed when electrons are _________________ from one atom to another

usually from an atom with one or two electrons in the outer shell to an atom that needs one or two electrons to fill its outer shell

◦ Transfer causes a ______ charge on the atom that gave up the electron and a ____________ charge on the atom that receives the electron.

◦ Since opposites attract, the two atoms “stick” together through electrostatic attraction.

______________Ions with a net positive charge.◦ Ca+, K+, Na+

_______________Ions with a net negative charge.◦ Cl-, F-

Ions are important in contraction of muscle fibers, transmission of nerve impulses, and maintenance of water balance.

________ bond between hydrogen atoms already ______________ bonded in a molecule to oppositely ______________ particles.

◦ (F,N,O)

Mostly formed between separate molecules, but can be formed between parts of the same large molecule (proteins and DNA), which can act to stabilize the molecule’s shape

The formation and breaking of chemical bonds.

Require energy input or release of energy.

Chemical Equation- reaction is described in written form.◦ X + Y → Z◦ (reactants) (products)

◦ Arrow indicates direction of the reaction

1. _______________ Reaction- new and more complex molecule is made from multiple, simpler chemicals. X + Y -> XY O + O -> O2

2. ___________________ Reaction- single complex chemical is broken down into multiple, simpler chemicals. XY -> X + Y 2H2O -> 2H2 + O2

3. ________________ Reaction- certain atoms are exchanged between molecules. Combination of synthesis and decomposition reaction.

WX + YZ -> WY + XZNaCl + AgNO3 -> NaNO3 + AgCl

+