1. Elements, Isotopes, Ions & the Periodic Table

2. Standard Atomic Notation
Ex: Carbon :
Atomic Number (Z=6)
Atomic Mass amu
(round to the nearest whole number)

3. For any atom the atomic number is equal to the number of protons and electrons.
All atoms MUST BE electrically neutral.

4. Question: Find the number of protons (p+),
Question: Find the number of protons (p+), neutrons (no), and electrons (e-).

5. The Periodic Table
Periodic Law – “when elements are arranged in order of increasing atomic mass, chemical and physical properties form patterns that repeat at regular intervals.”

7. Mendeleyev’s Periodic Table
In 1872, Mendeleyev organized a periodic table; he listed all elements known at the time using the periodic law. Mendeleyev left some blank spaces where known elements did not appear to fit. He suggested that elements would be discovered that would fit into these gaps. He was right.

8. The Modern Periodic Table
Family or Group – elements with similar chemical or physical properties are lined up in vertical columns.
Period – periods are the horizontal rows of elements and the properties of these elements change from metallic to non-metallic as we move from left to right.

9. Most periodic tables include:
the English name for each element
international symbol
atomic number
atomic mass *
physical state at SATP

10. * Atomic Mass – is defined relative to a carbon atom, which has a mass of 12 atomic mass units. Therefore an atomic mass unit (amu) is 1/12 of the mass of a carbon atom.
**SATP (standard ambient temperature and pressure) – is a set of conditions established by IUPAC to promote consistency when discussing properties of various substances. SATP refers to a temperature of 25 oC and a pressure of 100 kPa (kilopascals)
STP (standard temperature and pressure) – may also be used from time to time and is defined as 0 oC and kPa.

11. The Stair Case
The modern periodic table is divided by “the staircase line” which separates metals from non-metals.

12. Elements
All elements on the periodic table are represented by a symbol.
These symbols are either observed as a single capital letter or a capital letter followed by lower case letters.
Although there are many languages in the world and various elements have different names with respect to each language, the symbols on the periodic table are universal.

13. Who decides which symbols and names will be used?
A group of scientists belonging to the International Union of Pure and Applied Chemistry or IUPAC specify the rules for chemical names and symbols.

14. What does the Periodic Table Tell Us??

15. Names of Groups and Series of Elements
Group 1 metals are known as alkali metals
soft, silver colored metals
all react violently with water
Group 2 metals are known as alkaline-earth metals
all form oxide coatings (rust) in oxygen Ex: MgO, CaO
Group 17 elements are known as halogens
extremely reactive (Fluorine the most reactive)
Group 18 elements are known as noble gases
extremely unreactive

16. Groups 1, 2 and 13-18 are known as the representative elements
best follow the periodic law
Groups 3-12 are known as the transition elements or transition metals
exhibit a wide array of chemical and physical properties
do not follow the periodic law as closely as the representative elements
Lanthanides – (rare-earth elements) from atomic number 58-71
Actinides – from atomic number 90 to 103
Transuranic elements – all elements beyond uranium (atomic number 92)

17. Isotopes
We know that all atoms of the same elements are not completely identical. Some have different masses. This is caused by an increase in the number of neutrons of an element. Atoms that have the same number of protons but different number of neutrons are called isotopes:
Ex: carbon-12 & carbon-14

18. Ions
When atoms gain or lose electrons to fill their shells they turn into ions. Ions are atoms or groups of atoms that have a positive or negative charge.
Cations - Have a positive charge
Anions - Have a negative charge
When atom changes into an ion it drops the last three letters of its’ name and changes them to
-ide

19. Charges of ions are relative to the periodic table.
Halogens (17 or VIIA) - all make anions with a charge of -1
Group 16 or VIA - All make anions with a charge of -2
Group 15 or VA - All make anions with a charge of -3
Alkali Metals (1 or IA) - All make cations with a charge of +1
Alkali Earth Metals (2 or IIA) - All make cations with a charge of + 2

20. Transition metals (3-12) can have multiple charges
Transition metals (3-12) can have multiple charges. All make cations, but they can make different charges. These ions can be found on the periodic table.
Ex: Fe