Isotopes are atoms of the same element that have the same number of protons and electrons but a different number of neutrons . They share the same atomic number but have different mass numbers.

True or False? A positive ion (cation) is formed when an atom gains electrons.

False. A cation is formed when an atom loses electrons, giving it fewer electrons than protons. An atom that gains electrons forms a negatively charged ion called an anion .

Why do isotopes of the same element have identical chemical properties?

Isotopes of the same element have identical chemical properties because they have the same electron configuration . Since electrons determine chemical reactivity, all isotopes of an element react identically.

The number of neutrons in an atom = .......... (A) − .......... (Z)

The number of neutrons in an atom = mass number (A) − atomic number (Z)

Complete the table to show the relative charges of the subatomic particles. Particle Relative charge Proton .......... Neutron .......... Electron ..........

Particle Relative charge Proton +1 Neutron 0 Electron −1

What is relative atomic mass ( A r )?

Relative atomic mass ( A r ) is the weighted mean mass of an atom relative to 1/12th of the mass of a carbon-12 atom. It accounts for the natural abundance of each isotope.

True or False? Isotopes of the same element have different physical properties but the same chemical properties.

True. The different number of neutrons gives isotopes different masses, producing differences in physical properties such as density. Their identical electron configurations mean they share the same chemical properties .

How is the relative atomic mass ( A r ) of an element calculated from isotope data?

Relative atomic mass is calculated by multiplying each isotope's mass by its percentage abundance , summing the results, then dividing by 100.

True or False? In a mass spectrometer, heavier ions are deflected more than lighter ions.

False. Heavier ions move more slowly and are deflected less than lighter ions. Ions are separated according to their mass-to-charge ratio (m/z).

The stages of mass spectrometry in order are: Vaporisation .......... Acceleration ..........

The stages of mass spectrometry in order are: Vaporisation Ionisation Acceleration Detection

Why is "relative formula mass" used for ionic compounds rather than "relative molecular mass"?

Relative formula mass applies to ionic compounds because they have giant lattice structures with no discrete molecules. The formula represents a repeating unit, not a molecule, so "relative molecular mass" does not apply.

Define relative molecular mass ( M r )

A relative molecular mass ( M r ) is the sum of the relative atomic masses of all atoms in the molecular formula of a simple molecular compound .

True or False? In a mass spectrum, a peak with a larger signal indicates a higher abundance of that ion.

True. The height of each peak is proportional to the relative abundance of the ion at that m/z value. A larger signal means more ions of that mass were detected.

Define spectator ions

Spectator ions are ions present in a reaction mixture that do not take part in the chemical reaction. They appear on both sides of the full equation and are omitted from the ionic equation .

True or False? A Group 2 metal forms ions with a 2+ charge.

True. Group 2 metals lose 2 electrons from their outermost shell, forming 2+ ions . For example, calcium forms Ca 2+ .

What do Roman numerals in the name of a transition metal compound indicate?

Roman numerals indicate the charge (or oxidation state ) of the metal ion. For example, copper(II) indicates a Cu 2+ ion.

When balancing an equation, numbers called .......... are placed in front of chemical formulae. The chemical .......... themselves must never be changed.

When balancing an equation, numbers called coefficients are placed in front of chemical formulae. The chemical formulae themselves must never be changed.

Why must a chemical equation be balanced?

A chemical equation must be balanced because atoms are neither created nor destroyed in chemical reactions. The number of atoms of each element must be equal on both sides, obeying conservation of mass .

Complete the table of state symbols. State symbol Meaning (s) .......... (l) .......... (g) .......... (aq) ..........

State symbol Meaning (s) solid (l) liquid (g) gas (aq) aqueous (dissolved in water)

True or False? An ionic equation includes all ions present in solution, including those that do not react.

False. An ionic equation includes only the species that take part in the reaction. Ions that do not react ( spectator ions ) are removed from both sides.

A LevelChemistryOCRFlashcards2. Foundations in ChemistryAtoms & Reactions

Atoms & Reactions (OCR A Level Chemistry A): Flashcards

Exam code: H432

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Define isotopes

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Cards in this collection (20)

Define isotopes
Isotopes are atoms of the same element that have the same number of protons and electrons but a different number of neutrons. They share the same atomic number but have different mass numbers.
True or False?
A positive ion (cation) is formed when an atom gains electrons.
False.
A cation is formed when an atom loses electrons, giving it fewer electrons than protons. An atom that gains electrons forms a negatively charged ion called an anion.
Why do isotopes of the same element have identical chemical properties?
Isotopes of the same element have identical chemical properties because they have the same electron configuration. Since electrons determine chemical reactivity, all isotopes of an element react identically.
The number of neutrons in an atom = .......... (A) − .......... (Z)
The number of neutrons in an atom = mass number (A) − atomic number (Z)
Complete the table to show the relative charges of the subatomic particles.
Particle
Relative charge
Proton
..........
Neutron
..........
Electron
..........
Particle
Relative charge
Proton
+1
Neutron
0
Electron
−1
What is relative atomic mass (A_r)?
Relative atomic mass (A_r) is the weighted mean mass of an atom relative to 1/12th of the mass of a carbon-12 atom. It accounts for the natural abundance of each isotope.
True or False?
Isotopes of the same element have different physical properties but the same chemical properties.
True.
The different number of neutrons gives isotopes different masses, producing differences in physical properties such as density. Their identical electron configurations mean they share the same chemical properties.
How is the relative atomic mass (A_r) of an element calculated from isotope data?
Relative atomic mass is calculated by multiplying each isotope's mass by its percentage abundance, summing the results, then dividing by 100.
True or False?
In a mass spectrometer, heavier ions are deflected more than lighter ions.
False.
Heavier ions move more slowly and are deflected less than lighter ions. Ions are separated according to their mass-to-charge ratio (m/z).
The stages of mass spectrometry in order are:
1. Vaporisation
2. ..........
3. Acceleration
4. ..........
The stages of mass spectrometry in order are:
1. Vaporisation
2. Ionisation
3. Acceleration
4. Detection
Why is "relative formula mass" used for ionic compounds rather than "relative molecular mass"?
Relative formula mass applies to ionic compounds because they have giant lattice structures with no discrete molecules. The formula represents a repeating unit, not a molecule, so "relative molecular mass" does not apply.
Define relative molecular mass (M_r)
A relative molecular mass (M_r) is the sum of the relative atomic masses of all atoms in the molecular formula of a simple molecular compound.
True or False?
In a mass spectrum, a peak with a larger signal indicates a higher abundance of that ion.
True.
The height of each peak is proportional to the relative abundance of the ion at that m/z value. A larger signal means more ions of that mass were detected.
Define spectator ions
Spectator ions are ions present in a reaction mixture that do not take part in the chemical reaction. They appear on both sides of the full equation and are omitted from the ionic equation.
True or False?
A Group 2 metal forms ions with a 2+ charge.
True.
Group 2 metals lose 2 electrons from their outermost shell, forming 2+ ions. For example, calcium forms Ca²⁺.
What do Roman numerals in the name of a transition metal compound indicate?
Roman numerals indicate the charge (or oxidation state) of the metal ion. For example, copper(II) indicates a Cu²⁺ ion.
When balancing an equation, numbers called .......... are placed in front of chemical formulae. The chemical .......... themselves must never be changed.
When balancing an equation, numbers called coefficients are placed in front of chemical formulae. The chemical formulae themselves must never be changed.
Why must a chemical equation be balanced?
A chemical equation must be balanced because atoms are neither created nor destroyed in chemical reactions. The number of atoms of each element must be equal on both sides, obeying conservation of mass.
Complete the table of state symbols.
State symbol
Meaning
(s)
..........
(l)
..........
(g)
..........
(aq)
..........
State symbol
Meaning
(s)
solid
(l)
liquid
(g)
gas
(aq)
aqueous (dissolved in water)
True or False?
An ionic equation includes all ions present in solution, including those that do not react.
False.
An ionic equation includes only the species that take part in the reaction. Ions that do not react (spectator ions) are removed from both sides.

Particle	Relative charge
Proton	..........
Neutron	..........
Electron	..........

Particle	Relative charge
Proton	+1
Neutron	0
Electron	−1

State symbol	Meaning
(s)	..........
(l)	..........
(g)	..........
(aq)	..........

State symbol	Meaning
(s)	solid
(l)	liquid
(g)	gas
(aq)	aqueous (dissolved in water)

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