Elements, Compounds & Mixtures
What is a mixture?
A combination of two or more substances that are not chemically bonded.
What are the three main subatomic particles?
Protons, neutrons, and electrons.
What does the periodic table organize?
Elements, based on their atomic number and properties.
In the following reaction, what are the products:
Na + Cl --> NaCl
NaCl
What is an example of a compound?
i.e., Water (H₂O), Calcium chloride (CaCl2)
Where are protons located in an atom?
In the nucleus.
What is a group in the periodic table?
A vertical column that contains elements with SIMILAR CHEMICAL PROPERTIES.
What is the difference between a physical change and a chemical change?
A physical change does not alter the chemical composition, while a chemical change does.
What distinguishes an element from a compound?
Element: only 1 type of atom. Compound: 2+ different types of atoms that are chemically bonded.
What is the charge of an electron?
Negative.
What is the significance of the period number in the periodic table?
It indicates the number of electron shells an atom has.
What is an evidence of a chemical change?
What is a homogeneous mixture?
A mixture that has a uniform composition throughout, such as saltwater.
What is the atomic number of an element?
The number of protons (and electrons in the nucleus of an atom (protons = electrons).
Give an example of a noble gas.
He, Ne, Ar, Kr, Xe, Rn
What is the law of conservation of mass?
Matter is not created or destroyed in a chemical reaction.
How can you separate a mixture into its components?
filtration, distillation, chromatography.
How many neutrons does Bromine have (Atomic number: 35. Atomic mass: 79.9)
35 protons, 45 neutrons
How does the reactivity of metals change as you move down a group?
Reactivity increases as you move down a group.
What is an open system?
A system where matter can be exchanged with the surroundings. Substances can enter or leave the system freely.