Daily Science 1. Where are some places in the world that you can find the elements of the periodic table? 2. Can they combine with other elements? 3. Which of them do you think exist in our bodies? Try and list 5 of them.

Introduction to Biochemistry Grab your agendas and turn to the periodic table in the back!

Why Care About Chemistry? Life depends on chemistry. Chemical reactions keep our bodies living. Living things are made from chemical compounds. Everything is made up of atoms, the most basic unit of matter. There are more than 100 different types of atoms, although only two dozen are commonly found in living organisms.

Table 2-1 Table 2-1

(a) Nitrogen deficiency (b) Iodine deficiency Fig. 2-4 Figure 2.4 The effects of essential-element deficiencies (a) Nitrogen deficiency (b) Iodine deficiency

Atoms Atom – the most basic unit of matter. Made up of three subatomic particles: Electrons never stop moving Atoms have neutral charges because they have the same number of protons and electrons. Particle Abbreviation Charge Location Proton p+ Positive Nucleus Neutron n0 Neutral Electron e- Negative Orbitals

The Anatomy of an Atom Electrons Nucleus (protons + neutrons) Electron Orbital

Elements and the Periodic Table Element – a pure substance that consists entirely of one type of atom. These elements can be found on the periodic table. Elements are represented by one or two letter symbols. The first letter of this symbol is always capitalized.

Atomic Number C Label all parts and clues! Carbon 12.011 Atomic Number (#p and #e) 6 C Carbon 12.011 Symbol (1 or 2 letters) Element Name Atomic Mass (#p + #n)

C What does all this mean? If the atomic number changes so does the element In neutral atoms proton = electrons. Neutral because positive and negative match! What about finding neutron number? To find the number of neutrons, take the atomic mass – the atomic number 6 C Carbon 12.011

A=P=E M-A=N Atomic number = protons= electrons Mass number – atomic number= neutrons

Tell me About this Element What is the element name? Lithium What is the element symbol? Li What is the atomic number? 3 What is the atomic mass? 6.941 How many protons? How many electrons? How many neutrons? 4 3 Li Lithium 6.941

N Nitrogen 14.007 What is the element name? Nitrogen What is the element symbol? N What is the atomic number? 7 What is the atomic mass? 14.007 How many protons? How many electrons? How many neutrons? 7 N Nitrogen 14.007

Trends on the Periodic Table Dmitri Mendeleev was able to design the periodic table because he knew each element has one more proton than the element before it (even elements not discovered) As you move across the periodic table from left to right, the atomic number increases, meaning the atom increases in size. Elements in the same column react in the same way, and the reactions get stronger as you go down the column.