Science Practice Questions - Atoms, Bonding, and Reactions PDF

The number of protons in an atom is called its \_\_\_\_\_\_\_\_\_\_ number. Atomic The outermost electrons of an atom, which determine its bonding properties, are called \_\_\_\_\_\_\_\_\_\_ electrons. Valence The elements in Group 1 of the periodic table are known as \_\_\_\_\_\_\_\_\_\_ metals....

The number of protons in an atom is called its \_\_\_\_\_\_\_\_\_\_ number. Atomic The outermost electrons of an atom, which determine its bonding properties, are called \_\_\_\_\_\_\_\_\_\_ electrons. Valence The elements in Group 1 of the periodic table are known as \_\_\_\_\_\_\_\_\_\_ metals. Alkali The most stable elements, which rarely form compounds, are the \_\_\_\_\_\_\_\_\_\_ gases. Noble A chemical bond formed by the transfer of electrons is called an \_\_\_\_\_\_\_\_\_\_ bond. Ionic What is the purpose of insulation in a home? To reduce the transfer of heat, keeping the building warm in winter and cool in summer. How does a refrigerator keep food cold? It removes heat from the inside and transfers it outside using a refrigerant and a compressor. What is the difference between a passive and an active solar heating system? A passive system uses building materials to trap heat, while an active system uses pumps and fans to distribute heat. How does an internal combustion engine generate power? It burns fuel inside cylinders, creating expanding gases that move pistons. Why is atomic number used to organize the periodic table instead of atomic mass? Atomic number uniquely identifies elements and better reflects periodic trends. What did Rutherford's gold foil experiment reveal about the atom? That atoms have a small, dense, positively charged nucleus surrounded by mostly empty space. What makes noble gases chemically stable? They have a full outer electron shell, making them unlikely to react with other elements. How does an ionic bond form? One atom donates electrons to another, creating oppositely charged ions that attract each other. Why do alkali metals react so easily with other elements? They have only one valence electron, which they readily lose to achieve stability. What is the role of valence electrons in chemical bonding? They determine how atoms interact and form bonds with other atoms. An ionic bond forms when one atom \_\_\_\_\_\_\_\_\_\_ electrons to another atom. Transfers A covalent bond forms when two atoms \_\_\_\_\_\_\_\_\_\_ electrons. Share A substance that speeds up a chemical reaction without being consumed is called a \_\_\_\_\_\_\_\_\_\_. Catalyst The law of conservation of mass states that mass cannot be \_\_\_\_\_\_\_\_\_\_ or \_\_\_\_\_\_\_\_\_\_ in a chemical reaction. Created, Destroyed A reaction in which two or more substances combine to form a new compound is called a \_\_\_\_\_\_\_\_\_\_ reaction. Synthesis A reaction in which a compound breaks down into two or more simpler substances is called a \_\_\_\_\_\_\_\_\_\_ reaction. Decomposition A reaction in which one element replaces another in a compound is called a \_\_\_\_\_\_\_\_\_\_ reaction. Single-displacement A reaction in which ions from two compounds exchange places to form two new compounds is called a \_\_\_\_\_\_\_\_\_\_ reaction. Double-displacement The energy needed to start a chemical reaction is called \_\_\_\_\_\_\_\_\_\_ energy. Activation A substance that increases the number of hydronium ions when dissolved in water is called an \_\_\_\_\_\_\_\_\_\_. Acid A substance that increases the number of hydroxide ions when dissolved in water is called a \_\_\_\_\_\_\_\_\_\_. Base A reaction between an acid and a base that produces a salt and water is called a \_\_\_\_\_\_\_\_\_\_ reaction. Neutralization A solution with a pH below 7 is classified as \_\_\_\_\_\_\_\_\_\_. Acidic A solution with a pH above 7 is classified as \_\_\_\_\_\_\_\_\_\_. Basic An organic compound that contains only carbon and hydrogen is called a \_\_\_\_\_\_\_\_\_\_. Hydrocarbon A long chain of amino acids forms a \_\_\_\_\_\_\_\_\_\_. Protein The nucleic acid that carries genetic information in cells is called \_\_\_\_\_\_\_\_\_\_. DNA A radioactive particle consisting of two protons and two neutrons is called an \_\_\_\_\_\_\_\_\_\_ particle. Alpha The time required for half of a radioactive substance to decay is called its \_\_\_\_\_\_\_\_\_\_. Half-life Gamma radiation consists of high-energy \_\_\_\_\_\_\_\_\_. Electromagnetic waves What happens to mass during a chemical reaction? Mass is conserved; the total mass of reactants equals the total mass of products. How can you tell if a chemical reaction is occurring? By observing signs such as gas production, color change, temperature change, or precipitate formation. What is the difference between a catalyst and an inhibitor? A catalyst speeds up a reaction, while an inhibitor slows it down.