Fundamentals of Anatomy and Physiology

The Chemistry of Life

a Russian chemist, Dmitri Mendeleev (1834–1907), who
suggested that the elements could be arranged in groups
that showed similar physical and chemical properties. From
his work, we have the modern periodic table of the
elements, which arranges the elements by increasing atomic
number in such a way that similar properties re-peat at
periodic intervals (Figure 2 - 2).
In summary, protons and neutrons make up the nucleus
of an atom. Electrons orbit the nucleus. It is impossible to
know exactly where any given elec-tron is located at any
given moment, but the area

19

where it is found can be referred to as the electron’s orbital.

• Orbitals are grouped together to form energy levels
  consisting of electrons. Levels can contain more than one
  electron. Thus, atoms are represented as a round nucleus
  (containing protons and neutrons) surrounded- by
  concentric circles representing the en-ergy levels. Carbon
  has two electrons in the first level and four electrons in the
  second level. Hydrogen has a single electron in its first
  level and no other levels. Oxygen has two electrons in the
  first level and six elec-trons in the second level.

Chemical

H 1

Atomic (^)
symbol number (^)
Hydrogen (^) Chemical (^)
name^
(^) N (^7)
(^) Nitrogen
O
Number of 8
e– in each Oxygen
energy level (^)
Atomic (^) At. mass 1.00^1 Mg 12 C (^6)
mass Magnesium Carbon (^)
(^) H 2 • 5 (^)
At. mass 14.00
2 • 6
(^)
Na 11
(^)
Sodium Li^ Be^ B^ C^ N^ F^ Ne^ At. mass 16.00^
(^) Na Mg • 8 • 2 2 • 4 Al Si P S Cl Ar (^)
At. mass 24.30 At. mass 12.01 Cl (^17)
Chlorine (^)
(^) K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga As Se Br Kr (^)
2 • 8 • 1 (^) Rb Sr Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sb Te Xe
At. mass 22.99
P
15
(^)
(^)
K (^19) Cs Ba Ta W Re Os Ir Pt Phosphorus (^) Bi Pg Rn
Potassium
S^16 2 • 8 • 7^
Ca^20 Sulfur^ At. mass 35.45^
Fr Ra (A)
(^)
Calcium (^)

(L)

La Sm Eu Go^ 2 • 8 • 5^ Tm (^)
2 • 8 • 8 • 1 At. mass 30.97 (^)
At. mass 39.10 Ac Pu Am Cm Bk Cf Es Fm Md 2 • 8 • 6 (^)
(^) (A) 2 • 8 • 8 • 2 At. mass 32.06
(^) At. mass 40.08 (^)
Periodic Table
Figure 2- 2 The periodic table of the elements.
(^) ®
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