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WorksheetsScience Practice
Total questions: 54
Worksheet time: 27mins
How are elements arranged in the periodic table?
By increasing atomic mass
By increasing atomic number
Alphabetically
Randomly
Which of the following does a group in the periodic table represent?
The atomic mass of the element
The number of valence electrons
The total number of protons and neutrons
The energy levels of electrons
Which elements are located on the left side of the periodic table?
Non-metals
Metals
Metalloids
Noble gases
What are metalloids?
Elements with only metallic properties
Elements with only non-metallic properties
Elements with properties of both metals and non-metals
Elements that are gases at room temperature
Which of the following is NOT a property of non-metals?
Most are gases at room temperature
Brittle in solid form
Poor conductors of electricity
Good conductors of electricity
What charge does a neutron have?
Positive
Negative
Neutral
Both positive and negative
Where are electrons located in an atom?
Inside the nucleus
Orbiting the nucleus in energy levels
In the center with protons and neutrons
Scattered randomly in the atom
What does the atomic number of an atom represent?
The number of electrons
The number of neutrons
The number of protons
The total number of protons and neutrons
What are energy levels in an atom?
Regions where neutrons are located
Areas around the nucleus where electrons move
Layers of protons within the nucleus
Boundaries separating different atoms
What are valence electrons?
Electrons that are closest to the nucleus
Electrons in the outermost energy level
Neutrons that have gained energy
Protons that bond with electrons
How many valence electrons make an atom chemically stable?
2
6
8
10
Which of the following groups in the periodic table contains noble gases?
Group 1
Group 7
Group 18
Group 12
Which noble gas is stable with only 2 valence electrons?
Neon
Argon
Helium
Krypton
What is the purpose of the Lewis structure (electron dot diagram)?
To show the total number of electrons in an atom
To represent valence electrons around an element’s chemical symbol
To calculate the mass of an atom
To show the position of protons and neutrons
What happens to atoms with 1 to 7 valence electrons?
They are chemically stable.
They form chemical bonds to become stable.
They do not react chemically.
They form noble gases.
What is a compound?
A pure element
A mixture of elements
A substance made from two or more chemically bonded elements
An unstable molecule
What is an anion?
An atom that has gained or lost valence electrons
An atom with a neutral charge
An atom that contains only protons and neutrons
A substance that cannot conduct electricity
What charge does a metal atom typically have after losing valence electrons?
Negative
Neutral
Positive
Unstable
Which of the following is an example of an ionic compound?
CO₂
NaCl
H₂O
Mg
What is the result of a metallic bond?
Metals lose electrons and become positive ions.
Metal atoms share pooled valence electrons.
Non-metals gain electrons.
Metals form gases at room temperature.
What is a property of ionic compounds?
They are malleable.
They conduct electricity in solid form.
They have high melting points.
They are shiny.
What happens to valence electrons in a metallic bond?
They become tightly bound to the nucleus.
They transfer to non-metal atoms.
They are shared as a 'sea of electrons.'
They disappear.
Which of the following is NOT a property of metals?
Good conductor of electricity
Shiny
Brittle
Malleable
Why are metals good conductors of electricity?
They contain many protons.
Their electrons are tightly bound to the nucleus.
Their valence electrons are free to move.
They contain extra neutrons.
Which bond type is described by a 'sea of electrons'?
Covalent bond
Ionic bond
Metallic bond
Hydrogen bond
What is the formula of the ionic compound formed between potassium (K) and bromine (Br)?
KBr
K₂Br
K₂Br₃
K₃Br
What is the formula for the ionic compound formed between calcium (Ca) and phosphorus (P)?
Ca₃P
CaP₂
Ca₃P₂
Ca₂P₃
What is the formula for lithium chloride?
LiCl
LiCl₂
Li₂Cl
Li₂Cl₂
What is the formula for magnesium nitride?
MgN
Mg₃N₂
Mg₂N₃
Mg₃N
What is a covalent bond?
A bond formed by transferring electrons
A bond formed by sharing valence electrons
A bond formed by pooling electrons
A bond formed by gaining protons
Which of the following is a characteristic of covalent compounds?
High melting points
Good electrical conductivity
Poor electrical conductivity
Always solid at room temperature
What is the smallest particle of a covalent compound?
Atom
Molecule
Ion
Proton
Why is water a polar compound?
It has an equal sharing of electrons.
The oxygen atom pulls more strongly on shared electrons than hydrogen.
It has no electrons to share.
It contains a single covalent bond.
Which of the following best describes a chemical formula?
It shows the shape of a molecule.
It describes the elements and number of atoms in a compound.
It indicates the bond strength in a compound.
It represents the energy level of the compound.
Which bond is the strongest?
Single covalent bond
Double covalent bond
Triple covalent bond
Ionic bond
What does the Law of Conservation of Mass state?
Mass increases during chemical reactions.
Mass is created in chemical reactions.
Mass is neither created nor destroyed in a chemical reaction.
Mass is destroyed during chemical reactions.
Which of the following is NOT a sign of a chemical reaction?
Color change
Formation of a new gas
Melting
Light emission
What does a coefficient in a chemical equation represent?
The type of atom
The number of atoms or molecules
The shape of the molecule
The charge of the ion
What is the purpose of balancing a chemical equation?
To ensure equal mass on both sides
To determine the number of molecules
To predict the physical state of reactants
To measure the energy released
What happens during a chemical reaction?
Atoms are created.
Atoms rearrange and form new substances.
Bonds between atoms remain unchanged.
Molecules lose energy.
Which symbol represents a solid in a chemical equation?
(l)
(s)
(g)
(aq)
What is the purpose of a subscript in a chemical formula?
To show the charge of an atom
To represent the type of reaction
To indicate the number of atoms in a molecule
To show the physical state
What happens when atoms share electrons?
They form ionic bonds.
They form covalent bonds.
They lose valence electrons.
They gain electrons from the environment.
How does the number of shared electron pairs affect bond strength?
It weakens the bond.
It strengthens the bond.
It has no effect on the bond strength.
It causes the bond to break easily.
Which of the following statements about chemical formulas is correct?
They show the physical state of a molecule.
They describe the shape of the molecule.
They represent the elements and their proportions in a compound.
They indicate the energy levels of electrons.
What is the charge of an ion formed by an atom that gains electrons?
Neutral
Positive
Negative
Zero
What happens when a metal atom loses valence electrons?
It becomes negatively charged.
It becomes a positively charged ion.
It becomes chemically unstable.
It forms a covalent bond.
Which of the following best describes metallic bonding?
A metal atom transfers electrons to a nonmetal.
Valence electrons are shared equally between two atoms.
A 'sea of electrons' surrounds metal ions.
Metal atoms gain valence electrons to achieve stability.
Which of the following is an example of a chemical change?
Ice melting
Wood burning
Cutting a piece of paper
Water freezing
What is a precipitate?
A gas formed during a reaction
A solid that forms from a liquid solution during a reaction
A liquid formed by combining two solids
A chemical symbol used in equations
What happens when a chemical equation is not balanced?
The equation violates the Law of Conservation of Mass.
The reactants cannot form products.
The number of molecules changes.
The type of atoms changes.
In the reaction 2Na + Cl2 → 2NaCl, what does the coefficient '2' before Na represent?
The number of Na molecules
The number of Na atoms involved in the reaction
The number of electrons gained by Na
The amount of energy released
What does the arrow (→) in a chemical equation signify?
The end of a reaction
The separation of reactants from products
The physical state of the compounds
The charge of the ions
Why should polyatomic ions be treated as a single unit when balancing equations?
They do not affect the reaction.
Changing their subscripts alters the compound’s identity.
They cannot bond with other ions.
Their charges do not affect the balancing process.
