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Najla Awayda: 1) The first 92 elements apart from Technetium. Neptunium and Plutonium can occur in trace quantinties only where Uranium is found.
identical properties.
3) It helps in determining the valence state of an element.
Rinad Bakhti :
1- The elements to be found naturally are the primary 92 elements of the periodic table.
2- An isotope is an element which has an equal number of protons in the nucleus as another element or one with the same atomic number. Isotopes are elements which are similar to one another and have identical properties.
3- Atomic number determines the valence state of an element.

(2) Each vertical column refers to a family or group in the periodic table. The horizontal rows are called periods.
(3) The trends available are similarities of properties between elements of the same columns or rows.
Ibrahim Halawi: 1. Created by Dmitri Mendeleev in 1869.
2. Vertical column is called a family/group, the horizontal rows are named periods
3. SImilarities of properties from element to element of the the same row (period) or column (family)
Najla Awayda: (1) in 1869 by a Russian Chemist - Dmitri Mendeleev.
(2) The elements in columns, called groups, have the same number of electrons in the their outer orbital. The elements in the center section, transition elements, have special electron rules. The elements in rows, called periods, have the same number of atomic orbitals, the maximum number of orbitals for any element is seven.

{periodic-table_(3)_-_element_box.jpg}{periodic-table_(3)_-_element_box.jpg} 
Elements can be found in boxes at the intersection of rows and columns. Each element is described usually by a one letter or two letter acronym or symbol. In addition to an elements name and symbol, each box also describes several other characteristics. At the top left hand corner, one can find the atomic number of the element. This number describes the total mass of the protons neutrons and electrons in a single atom. And on the top right hand corner one can find the atomic weight of the element, which describes the ratio of the average mass of the element to 1/12 the mass of a carbon 12 isotope atom.

What are the uses for the atomic number of an element?

Najla Awayda: 1) The first 92 elements apart from Technetium. Neptunium and Plutonium can occur in trace quantinties only where Uranium is found.
2) Any 2 or more forms of a chemical element having the same number of protons in the nucleus, or the same atomic number, but having different number of neutrons,or different atomic weights. Isotopes of a single element possess almost identical properties.
3) It helps in determining the valence state of an element.

{periodic-table_(3).jpg}
The Periodic Table of Elements is the most wildly accepted way of organizing the know chemical elements of the universe into a structured and helpful chart. It is used in many fields of science including Chemistry, Biology, and Physics. It is divided into horizontal rows, or periods, and vertical columns, also called groups or families. There are 9 periods and 18 families. The periodic table of elements contains 118 chemical elements that have been discovered, each element can be found in a box at the intersection of a row and a column.
When was the modern periodic table created and by whom?
(2) Each vertical column refers to a family or group in the periodic table. The horizontal rows are called periods.
(3) The trends available are similarities of properties between elements of the same columns or rows.
Najla Awayda: (1) in 1869 by a Russian Chemist - Dmitri Mendeleev.
(2) The elements in columns, called groups, have the same number of electrons in the their outer orbital. The elements in the center section, transition elements, have special electron rules. The elements in rows, called periods, have the same number of atomic orbitals, the maximum number of orbitals for any element is seven.
(3) The ordering of the elements allows you to predict some of the properties of the elements relative to each other :
Atomic radius - half of the distance betwen the centers of two atoms that are touching each other (decreases moving left to right, increases moving top to bottom)
Electron affinity - alkaline earth, halogens, noble gases.
Ionization enegry - energy required to remove an electron ( increases moving left to right, decreases moving top to bottom)
Electronegativity - measure of the attraction to form a chemical bond (increases moving left to right, decreases moving top to bottom)

Najla Awayda
- Alkali Metals:
Ibrahim Halawi
Nazih Osseiran
Unit 16 The periodic table and its elements
View more presentations from Dr Samuel Aylward

Najla Awayda
- Alkali Metals:
Unit 16 The periodic table and its elements
View more presentations from Dr Samuel Aylward

{periodic-table_(3).jpg}{periodic-table_(3).jpg}
The Periodic Table of Elements is the most wildly accepted way of organizing the know chemical elements of the universe into a structured and helpful chart. It is used in many fields of science including Chemistry, Biology, and Physics. It is divided into horizontal rows, or periods, and vertical columns, also called groups or families. There are 9 periods and 18 families. The periodic table of elements contains 118 chemical elements that have been discovered, each element can be found in a box at the intersection of a row and a column.
When was the modern periodic table created and by whom?
What are some trends that can be found in the periodic table? Please describe them.

Rinad Bakhti: (1) Periodic table was created by Dmitri Mendeleev in 1869.
(2) Each vertical column refers to a family or group in the periodic table. The horizontal rows are called periods.
(3) The trends available are similarities of properties between elements of the same columns or rows.