Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

ATOM: The Building Block of
Universe
Dr
...


Each element in the periodic table has a unique atomic structure, and all atoms for
a given element have the same number of protons
...


The Bohr model is often referred to as the planetary model
...


For most practical purposes in electronics, the Bohr model suffices
and is commonly used because it is easy to visualize
...

❖ The nucleus consists of positively charged
particles called protons and uncharged
particles called neutrons
...

❖ Each type of atom has a certain number of
electrons and protons that distinguishes it
from the atoms of all other elements
...


Department of Electronics

5

Atomic Number
• All elements are arranged in the periodic table of the elements in
order according to their atomic number
...

For example, hydrogen has an atomic number of 1 and helium has an atomic number of
2
...


Department of Electronics

6

Atomic Number

Department of Electronics

7

Atomic Mass
• The atomic mass of a single atom is simply its total mass and is
typically expressed in atomic mass units or amu
...

• By definition, an atom of carbon with six neutrons/ six protons,
carbon-12, has an atomic mass of 12 amu
...

• In general, though, an atom's atomic mass will be very close to its
mass number but will have some deviation in the decimal places
...

• Electrons near the nucleus have less
energy than those in more distant orbits
...
Therefore, electrons
must orbit only at discrete distances
from the nucleus
...

• In an atom, the orbits are grouped into
energy levels known as shells
...

• Each shell has a fixed maximum number
of electrons
...

Department of Electronics

Illustration of the Bohr model of the silicon atom
...
The maximum number of electrons
that can ex

---