Atomic Structure

Haitham N. Alahmad

Element-It is a chemical substance that cannot be broken

down into simpler chemical form.

-There are 108 different chemical element in the nature e.g.hydrogen,carbon and oxygen.

-One element is entirely different from the other is due to the electronic configuration of their atoms

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Elements

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Compounds

-These are the result of two or more molecules linking together chemically e.g. water and salt

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Difference between an atom and a molecule

-Atom: smallest part of an element, which retains the chemical properties of the element.

-Molecule: smallest part of a compound, which retains the chemical properties of the matter.

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The structure of an atom(Niel Bohr`s theory of atom)

-An atom has 2 parts, at the center of the atom is the nucleus(which has positive charge+ve)and around nucleus are the circulating electrons (which has negative charge -ve).

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The structure of an atom(Niel Bohr`s theory of atom)

-Nucleus consist of 2 types:

1-Protons: which has Positive charge(+ve) equal and opposite to the charge of an electron.

2-Neutrons: which has no charge

*Neutrons and protons have same mass but the electrons is 2000times lighter than a Neutrons and protons ,proton mass

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The structure of an atom(Niel Bohr`s theory of atom)

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Atomic Number and atomic Mass-Atomic number:

It is an number of protons in the nucleus. It is symbol is `Z`.

-The chemical behavior of an atom is determined by its atomic number.

-Each element has a different atomic number e.g. H=1, He=2 ,C=6 and O=8.

-Atomic mass number:

It is the total number of protons and neutrons in the nucleus of the atom. It is symbol is `A`. He=4 because (2p+2n),O=16(8p+8n )

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Atomic Number and atomic Mass

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Isotope-Atoms having the same atomic number(Z)but

different atomic mass number are called isotopes. All isotopes have the same chemical properties as they have the same number of protons

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Types of Isotopes

-There are 2types of Isotope:

1-Radioactive Isotopes: which emit radiation, such as alph,beta,gamma rays.

2- Non-Radioactive Isotopes: which do not emit radiation

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Binding energy-It is the quantity of the energy required to remove an

electron from the shell is called binding energy of the electron. Depending on:

1- Type of shell, The outer shell electrons has the lowest binding energy whereas the inner shell has the highest binding energy.

2-The quantity of positive charge or the number of protons in the nucleus, the atomic number(Z).

The higher (Z),the greater binding energy.

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Ionization

-When an electron is removed from a neutral atom, the the atom will no longer remain neutral and the atom become positive charged

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