Subatomic particles
What is the charge of a proton?
Positive (+1)
What is an ion?
An atom with a different number of electrons than protons, giving it a charge.
What do elements in the same group have in common?
Same number of valence electrons
What is radioactive decay?
When unstable nuclei lose energy by emitting radiation.
What is a chemical reaction?
A process where substances change into new substances.
Which subatomic particle has no charge?
Neutron
What is an isotope?
Atoms of the same element with different numbers of neutrons.
Which group contains the noble gases?
Group 18
Name one type of radiation.
Alpha, beta, or gamma radiation
What is the name of the starting substances in a chemical reaction?
Reactants
Where are electrons located in an atom?
In energy levels (shells) around the nucleus
An atom has 17 protons and 18 electrons. What is its charge?
-1 (It has gained an electron.)
What is the atomic number of an element?
The number of protons in the atom
What happens to the atomic number during beta decay?
It increases by 1 (a neutron becomes a proton).
What is the difference between a physical and a chemical change?
Chemical changes form new substances; physical changes do not.
Which subatomic particle determines the identity of an element?
The number of protons
Carbon-12 and Carbon-14 are isotopes. What is the difference between them?
They have different numbers of neutrons (Carbon-14 has 2 more).
Why are elements in Group 1 so reactive?
They have 1 valence electron and want to lose it to become stable.
Which type of radiation can be stopped by paper?
Alpha radiation
In the reaction: 2H₂ + O₂ → 2H₂O, how many hydrogen atoms are in the reactants?
4 hydrogen atoms
An atom has 6 protons, 6 neutrons, and 7 electrons. Is it an atom or an ion, and what is its charge?
It is an ion with a -1 charge (more electrons than protons).
A neutral atom becomes a +2 ion. What happened to its electrons?
It lost 2 electrons.
Compare the reactivity of fluorine and iodine.
Fluorine is more reactive because it is higher up in Group 17
Why is gamma radiation more dangerous than alpha radiation?
Gamma can penetrate skin and most materials deeply, causing internal damage.
Explain how the Law of Conservation of Mass applies to chemical reactions.
The total mass of reactants equals the total mass of products; matter is not created or destroyed.