Physical & Chemical Properties
What is a physical property?
A characteristic that can be observed without changing the substance's identity.
What happens in an ionic bond?
Electrons are transferred from one atom to another, resulting in positive and negative ions.
Give an example of a physical change.
Ice melting into water or paper being torn.
What is the atomic number?
The number of protons in the nucleus of an atom, which determines the element's identity.
What is a compound?
A substance formed when two or more elements chemically bond together.
What is a chemical property?
A characteristic that describes how a substance can change into different substances through chemical reactions.
Give an example of a covalent bond.
Water (H₂O), where hydrogen and oxygen share electrons
What indicates a chemical change?
Signs include color change, gas production, temperature change, or formation of a precipitate.
What are groups and periods?
Groups are vertical columns in the periodic table, and periods are horizontal rows.
Give an example of a mixture.
Salad, trail mix, or air.
Name as man physical properties as you can. (100 points for each)
Color, density, boiling point, melting point, and solubility
How do ionic compounds behave?
They conduct electricity when dissolved in water and have high melting and boiling points.
Describe the conservation of mass.
In a closed system, the total mass before a change equals the total mass after the change.
What do elements in the same group have in common?
They have the same number of valence electrons.
What is the difference between homogeneous and heterogeneous mixtures?
Homogeneous mixtures are uniform throughout (like saltwater), while heterogeneous mixtures have visibly different parts (like sand and water)
What is solubility?
The ability of a substance to dissolve in a solvent, such as water.
What is a cation? What is a anion?
Cation - positive charged ion
Anion- negative charged ion
What is rusting an example of?
A chemical change, as it involves the transformation of iron into rust (iron oxide).
Explain the significance of valence electrons.
Valence electrons determine how an element will react chemically with other elements.
How are compounds separated?
Compounds can only be separated through chemical reactions, not physical methods.
How does density affect buoyancy?
An object will float if its density is less than the density of the fluid it is in.
Compare ionic and covalent compounds.
Ionic compounds form from electron transfer and are typically solid and brittle, while covalent compounds form from shared electrons and can be gases, liquids, or solids.
How can you tell if a change is chemical?
If new substances are formed with different properties from the original substances.
How does the periodic table help predict reactions?
It shows trends in reactivity, ionization energy, and electronegativity, helping to predict how elements will interact.
Name a common compound and its elements.
Water (H₂O) is made of hydrogen and oxygen.