Science - Acids and Bases ( Chemistry )
Checklist
Read the periodic table and find out the number of protons, neutrons and electrons an atom or its ion has, including
knowing the symbols for a range of elements
Describe atomic structure including electron arrangement
Understand how and why atoms form ions, and the types of ions metal and non-metals make
Explain the process of electron transfer
Know how to name ionic compounds, write the formula of ionic compounds and explain the ratio of ions
Explain what it means to be an acid and describe the properties of acids
Know basic acid base reactions with common acids and bases, including the products formed, writing word and formula
equations for these reactions
Understand what pH and the pH scale are, and estimate pH from information given, including testing pH with universal
indicator and litmus paper
Understand what neutralisation is and be able to explain this in terms of hydrogen ions and hydroxide ions
Atomic Structure
Protons - positive (atomic number)
Neutrons - neutral ( mass - atomic number)
Electrons - negative (atomic number)
Rows going across the periodic table are called periods, columns going down the table are called groups.
Metals are usually found on the left side of the periodic table and nonmetals are usually found on the right side.
Atoms form ions to achieve a more stable valence shell; they are formed when atoms gain or lose electrons, gaining electrons
results in a negative ion (anion), losing electrons results in a positive ion (cation).
Cations are positive ions that are formed when an atom loses electrons. Metals tend
+1 +2 +3 -3 -2 -1
to form cations because they have few electrons in their outer shell, so it’s easier for
them to lose electrons to achieve a full valence shell. H⁺ Mg²⁺ Al³⁺ N³⁻ O²⁻ Cl⁻
ie. Sodium (Na) has 1 electron in its outer shell. It loses 1 electron to achieve a full
valence shell, forming a sodium ion. Na⁺ Ca²⁺ Fe³⁺ CO₃²⁻ OH⁻
Anions are negative ions that are formed when an atom gains electrons. Non-metals K⁺ Fe²⁺ SO₄²⁻ NO₃
tend to form anions because they have more electrons in their outer shell, so it’s
Ag⁺ Cu²⁺ S²⁻ F⁻
easier for them to gain electrons to achieve a full valence shell.
ie. Chlorine (Cl) has 7 electrons in its outer shell. It gains 1 electron to achieve a full
Li⁺ Zn²⁺ Br⁻
valence shell, forming a chloride ion.
Pb²⁺
After the electron transfer, the metal cation and the non-metal anion are attracted to
each other due to their opposite charges, creating an ionic compound. Be²⁺
ie. Sodium (Na) transfers one electron to chlorine (Cl), resulting in the formation of Na⁺
and Cl⁻ ions.
Checklist
Read the periodic table and find out the number of protons, neutrons and electrons an atom or its ion has, including
knowing the symbols for a range of elements
Describe atomic structure including electron arrangement
Understand how and why atoms form ions, and the types of ions metal and non-metals make
Explain the process of electron transfer
Know how to name ionic compounds, write the formula of ionic compounds and explain the ratio of ions
Explain what it means to be an acid and describe the properties of acids
Know basic acid base reactions with common acids and bases, including the products formed, writing word and formula
equations for these reactions
Understand what pH and the pH scale are, and estimate pH from information given, including testing pH with universal
indicator and litmus paper
Understand what neutralisation is and be able to explain this in terms of hydrogen ions and hydroxide ions
Atomic Structure
Protons - positive (atomic number)
Neutrons - neutral ( mass - atomic number)
Electrons - negative (atomic number)
Rows going across the periodic table are called periods, columns going down the table are called groups.
Metals are usually found on the left side of the periodic table and nonmetals are usually found on the right side.
Atoms form ions to achieve a more stable valence shell; they are formed when atoms gain or lose electrons, gaining electrons
results in a negative ion (anion), losing electrons results in a positive ion (cation).
Cations are positive ions that are formed when an atom loses electrons. Metals tend
+1 +2 +3 -3 -2 -1
to form cations because they have few electrons in their outer shell, so it’s easier for
them to lose electrons to achieve a full valence shell. H⁺ Mg²⁺ Al³⁺ N³⁻ O²⁻ Cl⁻
ie. Sodium (Na) has 1 electron in its outer shell. It loses 1 electron to achieve a full
valence shell, forming a sodium ion. Na⁺ Ca²⁺ Fe³⁺ CO₃²⁻ OH⁻
Anions are negative ions that are formed when an atom gains electrons. Non-metals K⁺ Fe²⁺ SO₄²⁻ NO₃
tend to form anions because they have more electrons in their outer shell, so it’s
Ag⁺ Cu²⁺ S²⁻ F⁻
easier for them to gain electrons to achieve a full valence shell.
ie. Chlorine (Cl) has 7 electrons in its outer shell. It gains 1 electron to achieve a full
Li⁺ Zn²⁺ Br⁻
valence shell, forming a chloride ion.
Pb²⁺
After the electron transfer, the metal cation and the non-metal anion are attracted to
each other due to their opposite charges, creating an ionic compound. Be²⁺
ie. Sodium (Na) transfers one electron to chlorine (Cl), resulting in the formation of Na⁺
and Cl⁻ ions.
