Atom overview and subatomic particles
• Elements are made up of atoms.
• Atoms are made up of protons and
neutrons located within the nucleus, with
electrons in orbitals surrounding the
• Proton: positively charged particle in
the nucleus of all atoms
• Neutron: uncharged subatomic
particle in the nucleus
• Electron: negatively charged
subatomic particle that occupies
orbitals around the atomic nucleus
• Nucleus: core of atoms, occupied by
neutrons and protons
• Atomic number: number of protons in
the atomic nucleus, determines the
• Atomic Mass: total number of protons
and neutrons in the nucleus of an
• Isotope: element that differ in the
number of neutrons
• Radioisotope: isotope with instable
• Electrons have a negative charge and no mass.
• Protons have a positive charge and a mass of 1 unit.
• Neutrons have no electrical charge and a mass of 1 unit.
ESSENTIAL TO LIFE, DIVIDED INTO:
• BULK ELEMENTS: C, O, H, N
(Carbon, Oxygen, Hydrogen, Nitrogen)
• TRACE ELEMENTS: Fe, K, Na, Zn,
Ca (Iron, Potassium, Sodium, Zinc,
Trace elements (or trace metals)
are minerals present in living tissues in
living organisms is in a given concentration
2. The decreasing of abundance of
elements causes physiological changes
3. Administration of missing trace elements
improve the physiological condition.
They take part in the metabolism.
4. The elements have defined biochemical
pl. O2-transport: hemoglobin (Fe), hemocianin (Cu)
O2-storage: mioglobin (Fe)
2. Activation of molecules: metalloenzymes, enzymes activated
by metal ions:
a) catalysing of redox processes (Fe, Cu, Mn, Co, Mo, Ni)
biological oxidation, reduction of substrate
b) catalysing of acid-base processes (Zn)
3. Seconder conformation of macromolecules
– determination of conformation of enzymes
– determination of conformation of proteins, nucleic acids
4. Metabolism of microelements
– uptaking, transport, storage of trace elements
between two atoms when their electrons interact.
Covalent bond: chemical bond in which two atoms
share a pair of electrons.
Hydrogen bond: attraction between a bonded
hydrogen atom and another.
Ionic bond: bond in which a strong mutual attraction
forms between ions of opposite charge.
Molecule: group of two or more atoms joined by
Compound: type of molecule that has atoms of more
than one elements
Polarity: Any separation of charge into distinct
positive and negative regions.
Atoms accept, share, and donate
electrons; Whether an atom will
interact with other atoms depends
on how many electrons it has. A
chemical bond is the union of the
electron structures of atoms.
Atoms with an unfilled outer shell
tend to interact with other atoms in
ways that fill the shell, such as
forming chemical bonds.
Atoms with a filled outer shell are
inert- they do not form bonds.
• Valence electron is an electron that is
associated with an atom, and that can participate
in the formation of a chemical bond; occupies
Three types of bonds:
1. IONIC (giving up of e-); STRONG
2. COVALENT (non- polar and polar)
sharing of e-; STRONG
3. HYDROGEN between (hydrogen atom
which usually has a partial + charge, is
attracted to an atom w/ a partial - charge)
• when oppositely charged ions are
attracted to each other
• weaker than covalent bonds
• Na+Cl=NaCl=SODIUM CHLORIDE=
An atom with a positive or negative charge
due to loss or gain of electrons in its outer
Examples: Na+, ClIonic bonding takes place when the
difference in electronegativity between the
two atoms is more than 1.7
Opposite charges on two molecules are attracted to each other (F,O,N) + H.
Weakest type of bond.
required to make or break
Properties of Water:
- HYDROGEN bonds make it all