chemistry Overall Unit Flashcards
What is the atomic number of an element?
The atomic number is the number of protons in the nucleus of an atom.
True or False: The mass number of an atom is the sum of protons and neutrons.
True
Fill in the blank: The __________ is the smallest unit of an element that retains the properties of that element.
atom
What are the three main subatomic particles?
Protons, neutrons, and electrons.
What is the charge of a neutron?
Neutrons have no charge (neutral).
Which particle determines the identity of an element?
The proton.
What is the chemical formula for water?
H2O
True or False: An isotope of an element has the same number of protons but a different number of neutrons.
True
What is a molecule?
A molecule is a group of two or more atoms bonded together.
What type of bond involves the sharing of electron pairs between atoms?
Covalent bond.
What is the pH scale used for?
The pH scale measures the acidity or basicity of a solution.
What is the pH of pure water?
7 (neutral).
Fill in the blank: An __________ is a substance that increases the concentration of hydrogen ions in a solution.
acid
What do you call a substance that decreases the concentration of hydrogen ions in a solution?
Base.
What is the law of conservation of mass?
Mass is neither created nor destroyed in a chemical reaction.
True or False: A catalyst is a substance that speeds up a chemical reaction without being consumed.
True
What is the difference between an endothermic and exothermic reaction?
Endothermic reactions absorb heat, while exothermic reactions release heat.
What is the periodic table?
The periodic table is a tabular arrangement of elements based on their atomic number, electron configuration, and recurring chemical properties.
Which group of elements is known as alkali metals?
Group 1 elements.
What is the primary characteristic of noble gases?
Noble gases are inert and do not readily react with other elements.
What is the main difference between ionic and covalent bonds?
Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.
Fill in the blank: The __________ is the outermost shell of electrons in an atom.
valence shell
What is a chemical reaction?
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.
True or False: Reactants are the substances that are formed in a chemical reaction.
False
What is a balanced chemical equation?
A balanced chemical equation has equal numbers of each type of atom on both sides of the equation.
What is the significance of the coefficients in a chemical equation?
Coefficients indicate the relative amounts of reactants and products in a chemical reaction.
