Properties Of Matter Mid-term Prep Quiz 2018

An atom is the smallest part of an element that is considered the basic unit of matter. It consists of a nucleus, which contains protons and neutrons, and is surrounded by electrons. Atoms combine to form molecules, but they themselves are not molecules. The other options, such as the unit measure of an element or neutrons in the nucleus, do not accurately describe what an atom is.

The correct answer is "Anything that has mass and occupies space." This definition aligns with the scientific understanding of matter, which states that matter is anything that has mass (the amount of matter in an object) and occupies space (has volume). This definition encompasses a wide range of substances, including solids, liquids, and gases, as well as subatomic particles such as electrons.

An element is the term that best completes the statement. An element is a substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom and retains its chemical identity. Therefore, an element cannot be made simpler without changing its chemical make-up.

The given answer is correct because all the statements about solids, liquids, and gases are true. Solids have a definite volume and shape, and their atoms or molecules are strongly attracted to each other. Liquids have a definite volume but not a definite shape, and their atoms or molecules are attracted to each other. Gases do not have a definite volume or shape, and their atoms or molecules are barely attracted to each other. Therefore, all the statements are true.

Heating the bottle increases the motion of gas molecules inside the bottle, causing them to spread out easily and quickly. This increased motion leads to the molecules hitting the inside of the bottle and the bubble film harder and more often. The molecules push against the inside of the film with greater force than the surrounding air pushes from the outside, resulting in the formation of a bubble. When the bottle is cooled, the gas molecules slow down, hitting the film less often and with less force. The faster-moving molecules in the outside air push against the bubble from the outside, causing it to shrink and potentially go inside the bottle.

When the metal ball is heated, the increased motion of its atoms causes them to move slightly further apart, making the ball slightly larger. As a result, it will not fit through the ring. However, when the metal ball cools, the atoms slow down and their attractions bring them closer together. This allows the metal ball to fit through the ring again.

The kinetic-molecular theory states that matter can change between the phases of solid, liquid, and gas based on the energy of the particles. Temperature is the factor that determines the amount of energy the particles have. As temperature increases, the particles gain more energy and can overcome the attractive forces holding them together, causing a change in phase. Therefore, temperature is the key factor that affects the energy of particles and leads to phase changes in matter.

Hydrogen has an atomic number of one, meaning it has one proton in its nucleus and one electron in its outermost orbital. The outermost orbital can hold a maximum of two electrons, so a single hydrogen atom is unsatisfied and unstable with only one electron. However, when two hydrogen atoms combine to form a hydrogen molecule (H2), they share their electrons and fill each other's outermost orbitals. This sharing of electrons makes the hydrogen molecule more stable than two individual hydrogen atoms.

Valence electrons are different from other electrons because they are located in the outermost shell of an atom. This outer shell is involved in chemical bonding and interactions with other atoms. Valence electrons have the ability to be shared or transferred to other atoms, which allows for the formation of chemical bonds. This sharing or transferring of valence electrons is what enables atoms to combine and form molecules. In contrast, electrons in the core shells of an atom are not involved in bonding and are typically not easily shared or transferred. Therefore, the correct answer is that valence electrons can be shared or transferred with other atoms.

The explanation for the given correct answer is that according to the kinetic-molecular theory of matter, matter is composed of small particles called atoms and molecules. These particles are in constant motion, which means they are always moving. This theory helps to explain the behavior and properties of different states of matter, such as solids, liquids, and gases.

The statement that is correct about the number of protons and electrons in an atom is that the number of protons and the number of electrons in an atom are always equal. This is because the number of protons determines the atomic number of an element, and in a neutral atom, the number of electrons is equal to the number of protons, balancing out the positive charge of the protons with the negative charge of the electrons.

The atomic number of an atom refers to the number of protons in its nucleus. Protons carry a positive charge and are responsible for determining the element to which an atom belongs. By knowing the atomic number, one can identify the element and its properties. The other options provided in the question are incorrect. The number of protons and neutrons together is known as the mass number, not the atomic number. Valence electrons and electronegativity are unrelated to an atom's atomic number.

A chemical bond refers to the force that holds atoms together. This force is formed through the attraction between the positively charged nucleus of one atom and the negatively charged electrons of another atom. It is this bond that allows atoms to form molecules and compounds, creating a stable arrangement of atoms. This force can be formed through various mechanisms such as the exchange or sharing of valence electrons between atoms.

Hydrogen covalent bonds are non-polar because electrons in the bonds between identical atoms (H-H) are shared uniformly. This means that the electrons spend equal amounts of time around each atomic center. In a non-polar covalent bond, the electrons are evenly distributed between the two atoms, resulting in no significant difference in electronegativity. This uniform sharing of electrons leads to a non-polar molecule, as there is no separation of charge.

The number of protons determines what element it is and its chemical behavior because the number of protons in an atom's nucleus is unique to each element. This number is known as the atomic number and it defines the element's identity. The chemical behavior of an element is determined by the arrangement and interactions of its electrons, which are influenced by the number of protons in the nucleus. Therefore, the number of protons is crucial in determining both the identity and chemical behavior of an element.