This document defines and describes the basic concepts of elements, compounds, molecules, and subatomic particles. It states that elements are substances made of atoms with the same number of protons, while compounds contain atoms of different elements chemically combined in fixed ratios. Molecules are the smallest units that retain a compound's characteristics. The three main subatomic particles are protons, neutrons, and electrons, which make up atoms. The document also provides examples and properties of these scientific terms.

1. Elements, Compounds,
Molecules and Subatomic
particles
Kashish S, Kalika P and
Paranshi Z

2. Contents
• Elements
• Compounds
• Molecules
• Subatomic particles (protons, neutrons,
and electrons)
• Quiz

3. Elements
• ELEMENT is a substance consisting of
atoms which all have the same number
of protons - i.e. the same atomic number.
• Although an element's atoms must all
have the same number of protons, they
can have different numbers of neutrons
and hence different masses. When atoms
of the same element have different
numbers of neutrons, they are
called isotopes.

4. Compounds
• COMPOUND is a combination of 2 or more
elements in definite ratios by mass.
• The character of each element is lost when
forming a compound (e.g., think of NaCl).

5. Difference between
Compounds
• A compound contains
atoms of different
elements chemically
combined together in
a fixed ratio.
• A compound is
represented using a
formula.
• The list of compounds is
endless.
Elements
• An element is a pure
chemical substance
made of same type of
atom.
• An element is
represented using
symbols.
• There are about 117
elements that have
been observed. Can
be classified as metal,
non-metal or metalloid.

6. Molecules
• MOLECULES are the smallest units of a
compound that retains the
characteristics of the compound.
• The smallest particle of a substance that r
etains the chemical.
A group of like or different atoms held to
gether by chemical forces.

7. Subatomic particles
• The three main subatomic
particles that form an atom are
protons, neutrons, and electrons. The
center of the atom is called the
nucleus.

8. Neutrons
• Neutrons, with protons and electrons,
make up an atom. Neutrons and protons
are found in the nucleus of an
atom. Unlike protons, which have a
positive charge, or electrons, which have
a negative charge, neutrons
have zero charge. Neutrons bind with
protons. Neutrons were predicted
by Ernest Rutherford, and discovered
by James Chadwick, in 1932.

9. Electron
• Electron is a very small piece
of matter and energy. Its symbol is e−.
The electron is a subatomic particle. It
is believed to be an elementary
particle because it cannot be broken
down into anything smaller. It is
negatively charged, and may move
almost at the speed of light.

10. Proton
• Proton is part of an atom. They are found
in the nucleus of an atom along
with neutrons. The periodic table groups
atoms according to how many protons
they have. A single atom of hydrogen is
made up of an electron moving around
a proton. Most of the mass of this atom is
in the proton, which is almost 2000 times
heavier than the electron. Protons
and neutrons make up the nucleus of
every other kind of atom.

12. Q1) Carbon Dioxide Is Made Up Of A
Carbon Atom And 2 Oxygen Atoms.
What Is It’s Formula?
• CO2
• Carbon dioxide is a colorless, non-
organic compound that is a gas at
room temperature and comprises
about 0.03 percent of Earth's
atmosphere.

13. Q2) What Is The SI Unit For
Atomic Mass
• AMU (atomic mass unit)
• An atomic mass unit is defined as
precisely 1/12 the mass of an atom of
carbon-12. The carbon-12 (C-12) atom
has six protons and six neutrons in its
nucleus.

14. Q3) State One Difference Between
Element And Compound
• A compound is represented using a
formula.
• An element is represented using
symbols.

15. Q4)After seeing the image tell the
name of the following element :
• Na
• Sodium
• Cl
• Chlorine
• K
• Potassium