CHEMISTRY REVISION GCSE ALL TOPICS
IONIC BONDS
Ionic bonds are a type of chemical bond that forms
between two atoms when one atom donates electrons to
another, leading to the creation of ions. These bonds are
characterized by the electrostatic attraction between
positively and negatively charged ions.
Here’s a step-by-step explanation of how ionic bonds form:
1. Electron Transfer: Ionic bonding begins with the
transfer of electrons from one atom to another.
Typically, this occurs between a metal atom and a
non-metal atom. Metals, which are found on the left
side of the periodic table, have few electrons in their
outer shell and tend to lose these electrons. Non-
metals, located on the right side of the periodic table,
have more electrons in their outer shell and tend to
gain electrons to achieve a full outer shell.
2. Formation of Ions: When a metal atom loses one or
more electrons, it becomes a positively charged ion
(cation). Conversely, when a non-metal atom gains
electrons, it becomes a negatively charged ion
(anion). For instance, sodium (Na), a metal, loses an
electron to become a sodium ion (Na⁺), and chlorine
(Cl), a non-metal, gains an electron to become a
chloride ion (Cl⁻).
3. Electrostatic Attraction: The oppositely charged ions
(cation and anion) are attracted to each other due to
electrostatic forces. This attraction is what holds the
ions together in an ionic bond.
, 4. Formation of Ionic Compounds: The result of this
attraction is the formation of an ionic compound. In
the case of sodium chloride (NaCl), the Na⁺ and Cl⁻
ions come together to form a stable, electrically
neutral compound.
5. Crystal Lattice Structure: Ionic compounds usually
form a crystalline structure in which ions are
arranged in a repeating pattern. This lattice structure
maximizes the attractive forces between ions and
minimizes repulsive forces, contributing to the
stability of the compound.
To summarize, ionic bonds form through the transfer of
electrons from a metal to a non-metal, resulting in the
creation of positively and negatively charged ions that
attract each other to form stable ionic compounds.
STATES OF MATTER
The states of matter describe the different forms that
matter can take, and understanding these is a key part of
GCSE science. Matter generally exists in four main states:
solid, liquid, gas, and plasma. Here’s a straightforward
explanation of each state and how they change from one
to another:
1. Solid
• Characteristics: In a solid, particles (atoms or
molecules) are tightly packed together in a fixed,
orderly arrangement. This arrangement means solids
have a definite shape and volume. The particles
vibrate but do not move from their fixed positions.
, • Example: Ice, a rock, or a wooden table.
2. Liquid
• Characteristics: In a liquid, particles are close
together but not in a fixed position. They can move
around each other, which allows liquids to flow and
take the shape of their container while maintaining a
definite volume.
• Example: Water, milk, or oil.
3. Gas
• Characteristics: In a gas, particles are far apart and
move freely. This means gases do not have a definite
shape or volume. They expand to fill the entire space
available to them, spreading out to fit the container.
• Example: Air, helium, or carbon dioxide.
4. Plasma
• Characteristics: Plasma is a state of matter where
the gas particles have been energized to the point
that some electrons are stripped from their atoms,
creating a mixture of free electrons and ions. Plasma
conducts electricity and is affected by magnetic
fields. It doesn’t have a definite shape or volume.
• Example: The sun, lightning, or neon lights.
Changing States
Matter can change from one state to another through
physical processes. Here’s how these changes occur:
• Melting: Solid to liquid (e.g., ice melting into water).
• Freezing: Liquid to solid (e.g., water freezing into ice).
IONIC BONDS
Ionic bonds are a type of chemical bond that forms
between two atoms when one atom donates electrons to
another, leading to the creation of ions. These bonds are
characterized by the electrostatic attraction between
positively and negatively charged ions.
Here’s a step-by-step explanation of how ionic bonds form:
1. Electron Transfer: Ionic bonding begins with the
transfer of electrons from one atom to another.
Typically, this occurs between a metal atom and a
non-metal atom. Metals, which are found on the left
side of the periodic table, have few electrons in their
outer shell and tend to lose these electrons. Non-
metals, located on the right side of the periodic table,
have more electrons in their outer shell and tend to
gain electrons to achieve a full outer shell.
2. Formation of Ions: When a metal atom loses one or
more electrons, it becomes a positively charged ion
(cation). Conversely, when a non-metal atom gains
electrons, it becomes a negatively charged ion
(anion). For instance, sodium (Na), a metal, loses an
electron to become a sodium ion (Na⁺), and chlorine
(Cl), a non-metal, gains an electron to become a
chloride ion (Cl⁻).
3. Electrostatic Attraction: The oppositely charged ions
(cation and anion) are attracted to each other due to
electrostatic forces. This attraction is what holds the
ions together in an ionic bond.
, 4. Formation of Ionic Compounds: The result of this
attraction is the formation of an ionic compound. In
the case of sodium chloride (NaCl), the Na⁺ and Cl⁻
ions come together to form a stable, electrically
neutral compound.
5. Crystal Lattice Structure: Ionic compounds usually
form a crystalline structure in which ions are
arranged in a repeating pattern. This lattice structure
maximizes the attractive forces between ions and
minimizes repulsive forces, contributing to the
stability of the compound.
To summarize, ionic bonds form through the transfer of
electrons from a metal to a non-metal, resulting in the
creation of positively and negatively charged ions that
attract each other to form stable ionic compounds.
STATES OF MATTER
The states of matter describe the different forms that
matter can take, and understanding these is a key part of
GCSE science. Matter generally exists in four main states:
solid, liquid, gas, and plasma. Here’s a straightforward
explanation of each state and how they change from one
to another:
1. Solid
• Characteristics: In a solid, particles (atoms or
molecules) are tightly packed together in a fixed,
orderly arrangement. This arrangement means solids
have a definite shape and volume. The particles
vibrate but do not move from their fixed positions.
, • Example: Ice, a rock, or a wooden table.
2. Liquid
• Characteristics: In a liquid, particles are close
together but not in a fixed position. They can move
around each other, which allows liquids to flow and
take the shape of their container while maintaining a
definite volume.
• Example: Water, milk, or oil.
3. Gas
• Characteristics: In a gas, particles are far apart and
move freely. This means gases do not have a definite
shape or volume. They expand to fill the entire space
available to them, spreading out to fit the container.
• Example: Air, helium, or carbon dioxide.
4. Plasma
• Characteristics: Plasma is a state of matter where
the gas particles have been energized to the point
that some electrons are stripped from their atoms,
creating a mixture of free electrons and ions. Plasma
conducts electricity and is affected by magnetic
fields. It doesn’t have a definite shape or volume.
• Example: The sun, lightning, or neon lights.
Changing States
Matter can change from one state to another through
physical processes. Here’s how these changes occur:
• Melting: Solid to liquid (e.g., ice melting into water).
• Freezing: Liquid to solid (e.g., water freezing into ice).
