Compare Atomic Structures - Middle School Physical Science
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What is the smallest unit that still has the properties of an element?
What is the smallest unit that still has the properties of an element?
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An atom. Individual atoms retain all elemental properties.
An atom. Individual atoms retain all elemental properties.
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Which option indicates a heterogeneous mixture in a particle model: uniform or clumped distribution?
Which option indicates a heterogeneous mixture in a particle model: uniform or clumped distribution?
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Clumped or non-uniform distribution. Heterogeneous mixtures have visibly uneven particle distribution.
Clumped or non-uniform distribution. Heterogeneous mixtures have visibly uneven particle distribution.
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Identify the substance type: a model shows identical bonded pairs of two different colors.
Identify the substance type: a model shows identical bonded pairs of two different colors.
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Compound. Different colored spheres bonded together indicate different elements.
Compound. Different colored spheres bonded together indicate different elements.
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Which formula matches a model with $2$ atoms of $A$ bonded to $3$ atoms of $B$ per particle?
Which formula matches a model with $2$ atoms of $A$ bonded to $3$ atoms of $B$ per particle?
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$A_2B_3$. Subscripts directly indicate atom counts in the formula.
$A_2B_3$. Subscripts directly indicate atom counts in the formula.
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Which formula shows a $1:2$ atom ratio between the first and second elements: $AB_2$ or $A_2B$?
Which formula shows a $1:2$ atom ratio between the first and second elements: $AB_2$ or $A_2B$?
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$AB_2$. Subscript 2 on B means two B atoms per one A atom.
$AB_2$. Subscript 2 on B means two B atoms per one A atom.
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Identify the substance type: a model shows two different unbonded particle types mixed together.
Identify the substance type: a model shows two different unbonded particle types mixed together.
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Mixture of elements. Different unbonded particles mixed together form mixtures.
Mixture of elements. Different unbonded particles mixed together form mixtures.
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Identify the structure type: a model shows an extended repeating lattice of two ion types.
Identify the structure type: a model shows an extended repeating lattice of two ion types.
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Ionic compound (formula units in a lattice). Ionic compounds form extended lattices, not discrete molecules.
Ionic compound (formula units in a lattice). Ionic compounds form extended lattices, not discrete molecules.
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What term describes a repeating 3D pattern of particles in many solids, such as salts?
What term describes a repeating 3D pattern of particles in many solids, such as salts?
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Crystal lattice. Repeating 3D patterns form crystalline structures.
Crystal lattice. Repeating 3D patterns form crystalline structures.
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What is the smallest unit that still has the properties of a molecular compound?
What is the smallest unit that still has the properties of a molecular compound?
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A molecule. Molecules are the smallest units of molecular compounds.
A molecule. Molecules are the smallest units of molecular compounds.
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Which option indicates a homogeneous mixture in a particle model: uniform or clumped distribution?
Which option indicates a homogeneous mixture in a particle model: uniform or clumped distribution?
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Uniform distribution of different particles. Homogeneous mixtures have evenly distributed components throughout.
Uniform distribution of different particles. Homogeneous mixtures have evenly distributed components throughout.
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What pattern in a particle model shows a substance has a fixed composition?
What pattern in a particle model shows a substance has a fixed composition?
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All particles are identical repeating units. Fixed composition requires consistent particle structure throughout.
All particles are identical repeating units. Fixed composition requires consistent particle structure throughout.
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What is the definition of an element in terms of atomic composition?
What is the definition of an element in terms of atomic composition?
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A pure substance made of only one type of atom. Elements contain only one atomic type, making them fundamentally pure.
A pure substance made of only one type of atom. Elements contain only one atomic type, making them fundamentally pure.
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What is the definition of a compound in terms of atomic composition?
What is the definition of a compound in terms of atomic composition?
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A substance made of two or more elements chemically bonded in fixed ratios. Chemical bonds create definite proportions between different elements.
A substance made of two or more elements chemically bonded in fixed ratios. Chemical bonds create definite proportions between different elements.
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What is the definition of a mixture in terms of atomic composition?
What is the definition of a mixture in terms of atomic composition?
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A physical blend of substances not chemically bonded; composition can vary. No chemical bonds means components retain individual properties.
A physical blend of substances not chemically bonded; composition can vary. No chemical bonds means components retain individual properties.
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Which statement best describes atoms in a pure element sample: same or different types?
Which statement best describes atoms in a pure element sample: same or different types?
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Same type of atom throughout. Elements by definition contain only one atomic type.
Same type of atom throughout. Elements by definition contain only one atomic type.
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Which model feature indicates a compound rather than a mixture: bonded groups or separate particles?
Which model feature indicates a compound rather than a mixture: bonded groups or separate particles?
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Bonded groups of different atoms repeating. Chemical bonds between different atoms define compounds.
Bonded groups of different atoms repeating. Chemical bonds between different atoms define compounds.
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What does a chemical formula represent about atomic composition?
What does a chemical formula represent about atomic composition?
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The types of atoms present and their whole-number ratios. Formulas show element symbols and numerical subscripts for ratios.
The types of atoms present and their whole-number ratios. Formulas show element symbols and numerical subscripts for ratios.
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What does a subscript in a chemical formula indicate about a substance’s structure?
What does a subscript in a chemical formula indicate about a substance’s structure?
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The number of atoms of that element in one molecule or formula unit. Subscripts count atoms per molecule or formula unit.
The number of atoms of that element in one molecule or formula unit. Subscripts count atoms per molecule or formula unit.
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Identify the substance type: a model shows only single, unbonded identical spheres.
Identify the substance type: a model shows only single, unbonded identical spheres.
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Element (monatomic model). Single unbonded identical spheres represent individual atoms.
Element (monatomic model). Single unbonded identical spheres represent individual atoms.
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Identify the substance type: a model shows pairs of identical spheres bonded together.
Identify the substance type: a model shows pairs of identical spheres bonded together.
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Element (diatomic molecules). Some elements exist as diatomic molecules like $O_2$ or $N_2$.
Element (diatomic molecules). Some elements exist as diatomic molecules like $O_2$ or $N_2$.
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What particle types are shown in an ionic compound model at the atomic level?
What particle types are shown in an ionic compound model at the atomic level?
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Cations and anions arranged in a repeating pattern. Positive and negative ions balance charges in the crystal structure.
Cations and anions arranged in a repeating pattern. Positive and negative ions balance charges in the crystal structure.
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Which option indicates a molecular compound model: discrete molecules or an extended repeating lattice?
Which option indicates a molecular compound model: discrete molecules or an extended repeating lattice?
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Discrete molecules. Molecules exist as separate units held by intermolecular forces.
Discrete molecules. Molecules exist as separate units held by intermolecular forces.
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What does a chemical formula represent about a substance’s atomic composition?
What does a chemical formula represent about a substance’s atomic composition?
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The types and fixed ratios of atoms in each particle. Subscripts show the exact number of each atom type.
The types and fixed ratios of atoms in each particle. Subscripts show the exact number of each atom type.
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Which model feature shows that a sample is a mixture: identical particles or more than one particle type?
Which model feature shows that a sample is a mixture: identical particles or more than one particle type?
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More than one particle type. Different particle types can be separated by physical means.
More than one particle type. Different particle types can be separated by physical means.
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Which formula represents a compound with a $2:1$ atom ratio of hydrogen to oxygen?
Which formula represents a compound with a $2:1$ atom ratio of hydrogen to oxygen?
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$H_2O$. Two hydrogen atoms bond with one oxygen atom in water.
$H_2O$. Two hydrogen atoms bond with one oxygen atom in water.
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