The chemical context of life

Key concepts Matter consists of chemical elements in pure form and in combinations called compounds An element’s properties depend on the structure of its atoms The formation and function of molecules depend on chemical bonding between atoms Chemical reactions make and break chemical bonds

Matter consists of chemical elements in pure form and combinations called compounds

Matter consists of chemical elements in pure form and combinations called compounds What is matter?

Matter consists of chemical elements in pure form and combinations called compounds Something that has mass and occupies space Matter consists of atoms

Matter consists of chemical elements in pure form and combinations called compounds Something that has mass and occupies space Matter consists of atoms What are atoms?

Matter consists of chemical elements in pure form and combinations called compounds Something that has mass and occupies space Matter consists of atoms Atoms are the fundamental building block of all substances. The smallest unit of matter that retains the properties of an element

Matter consists of chemical elements in pure form and combinations called compounds Something that has mass and occupies space Matter consists of atoms Atoms are the fundamental building block of all substances. The smallest unit of matter that retains the properties of an element. What is an element?

Matter consists of chemical elements in pure form and combinations called compounds Something that has mass and occupies space Matter consists of atoms Atoms are the fundamental building block of all substances. The smallest unit of matter that retains the properties of an element. An element is a substance that cannot be broken down into other substances by chemical reaction.

Matter consists of chemical elements in pure form and combinations called compounds Something that has mass and occupies space Matter consists of atoms Atoms are the fundamental building block of all substances. The smallest unit of matter that retains the properties of an element. Why? An element is a substance that cannot be broken down into other substances by chemical reaction.

Matter consists of chemical elements in pure form and combinations called compounds Each element is composed on a single type of atom Compounds are made of more than one element in a fixed ratio hydrogen and oxygen gold sodium and chloride

Matter consists of chemical elements in pure form and combinations called compounds Whether they are in compounds or in pure form, there are relatively few elements in living organisms

Matter consists of chemical elements in pure form and combinations called compounds

An element’s properties depend on the structure of its atoms

An element’s properties depend on the structure of its atoms What do we mean by properties?

An element’s properties depend on the structure of its atoms Properties-melting point, bonding, and density are common examples.

An element’s properties depend on the structure of its atoms Atomic structure Electron cloud Nucleus

An element’s properties depend on the structure of its atoms Atomic structure Electron cloud Contains: Electrons Nucleus Contains: Protons Neutrons

An element’s properties depend on the structure of its atoms Atomic structure Electron cloud Contains: Electrons He Nucleus Contains: Protons Neutrons 2 All atoms of the same element will have the same number of protons (Atomic number)

An element’s properties depend on the structure of its atoms Atomic structure Electron cloud Contains: Electrons He Nucleus Contains: Protons Neutrons 2 All atoms of the same element will have the same number of protons (Atomic number) The number of neutrons typically equals the number of protons

An element’s properties depend on the structure of its atoms Atomic structure Electron cloud Contains: Electrons He 4 Nucleus Contains: Protons Neutrons 2 All atoms of the same element will have the same number of protons (Atomic number) The number of neutrons typically equals the number of protons Mass number is the number of protons + number of neutrons

An element’s properties depend on the structure of its atoms Atomic structure Electron cloud Contains: Electrons He 4 Nucleus Contains: Protons Neutrons 2 All atoms of the same element will have the same number of protons (Atomic number) The number of neutrons typically equals the number of protons Mass number is the number of protons + number of neutrons The number of electrons typically equals the number of protons

What is the atomic number of Aluminum?

How many protons does Lithium have?

What is the mass number of Chloride?

An element’s properties depend on the structure of its atoms Atomic structure Electron cloud Contains: Electrons He 3 Nucleus Contains: Protons Neutrons 2 All atoms of the same element will have the same number of protons (Atomic number) The number of neutrons typically equals the number of protons (not for isotopes) Mass number is the number of protons + number of neutrons The number of electrons typically equals the number of protons

An element’s properties depend on the structure of its atoms Atomic structure Electron cloud Contains: Electrons He + 4 Nucleus Contains: Protons Neutrons 2 All atoms of the same element will have the same number of protons (Atomic number) The number of neutrons typically equals the number of protons (not for isotopes) Mass number is the number of protons + number of neutrons The number of electrons typically equals the number of protons (not for ions)

An element’s properties depend on the structure of its atoms Atomic structure Focusing on electrons- Atomic nuclei don’t interact, electrons do Electrons vary in the amount of energy they possess because of their position relative to the nucleus. They are attracted to the nucleus It takes work (energy) to be far from it They reside in energy levels (shells)

An element’s properties depend on the structure of its atoms Atomic structure Focusing on electrons- Atomic nuclei don’t interact, electrons do

An element’s properties depend on the structure of its atoms Atomic structure Focusing on electrons-The chemical behavior of an atom is determined by the distribution of its electrons Hydrogen 1H Lithium 3Li Beryllium 4Be Boron 5B Carbon 6C Nitrogen 7N Oxygen 8O Fluorine 9F Neon 10Ne Helium 2He First shell Second Third Sodium 11Na Magnesium 12Mg Aluminum 13Al Silicon 14Si Phosphorus 15P Sulfur 16S Chlorine 17Cl Argon 18Ar

An element’s properties depend on the structure of its atoms

The formation and function of molecules depend on chemical bonding between atoms

The formation and function of molecules depend on chemical bonding between atoms Different types of bonds Covalent bonds (strongest) - involves the sharing of electrons (i.e. H2) Electrons may be spread equally across the bond (non-polar bond) Electrons may not be spread equally across the bond (polar bond)

The formation and function of molecules depend on chemical bonding between atoms Natural endorphin Morphine Endorphin receptors Brain cell (b) Binding to endorphin receptors

The formation and function of molecules depend on chemical bonding between atoms Different types of bonds Covalent bonds (strongest) - involves the sharing of electrons (i.e. H2) Electrons may be spread equally across the bond (non-polar bond) Electrons may not be spread equally across the bond (polar bond) Ionic bonds- Charge-charge interactions An interaction between a positive and negative charge Can form after one atoms strips a valence electron from another (ie. NaCl) Forms salts

The formation and function of molecules depend on chemical bonding between atoms Ionic bond Electron transfer forms ions Na Sodium atom Cl Chlorine atom Na+ Sodium ion (a cation) Cl– Chloride ion (an anion)

Which elements will most likely form an ionic bond? a. Li and F b. C and O c. N and O d. Si and Cl e. H and H

The formation and function of molecules depend on chemical bonding between atoms Different types of bonds (weak) Hydrogen bonds- involve polar covalent bonds, form when a hydrogen atom is bonded to a more electronegative atom

The formation and function of molecules depend on chemical bonding between atoms Different types of bonds (weak) Hydrogen bonds- involve polar covalent bonds, form when a hydrogen atom is bonded to a more electronegative atom This impacts the properties of water!

The formation and function of molecules depend on chemical bonding between atoms Different types of bonds (weak) Hydrogen bonds- involve polar covalent bonds, form when a hydrogen atom is bonded to a more electronegative atom Vander Waals interactions- involve non-polar covalent bonds, occur when an electron accumulation arises by chance

The formation and function of molecules depend on chemical bonding between atoms

Chemical reactions make and break chemical bonds

Chemical reactions make and break chemical bonds Chemical reaction- making a breaking of chemical bonds leading to changes in the composition of matter

Chemical reactions make and break chemical bonds Chemical reaction- making a breaking of chemical bonds leading to changes in the composition of matter 6 CO2 + 6 H2O C6H12O6 + 6O2

Chemical reactions make and break chemical bonds

Key concepts Matter consists of chemical elements in pure form and in combinations called compounds An element’s properties depend on the structure of its atoms The formation and function of molecules depend on chemical bonding between atoms Chemical reactions make and break chemical bonds