Physical Science Chapter 19

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Transition metals have partially filled d orbitals, which can absorb certain wavelengths of light. When light is absorbed, electrons in the d orbitals are promoted to higher energy levels. The energy difference between the absorbed and emitted light corresponds to visible light, resulting in the compound appearing colored. Therefore, compounds containing transition metals often exhibit vibrant and distinct colors.

The structural organization of water refers to how the water molecules are arranged and organized. Water is a molecular substance, meaning it consists of individual water molecules held together by covalent bonds. These molecules are organized in a specific way due to the polarity of water, with the oxygen atom attracting the hydrogen atoms and creating a bent shape. Therefore, the correct answer is "molecular substances" as it accurately describes the structural organization of water.

A chemical bond refers to the attractive interaction between atoms that holds them together in molecules. This bond is formed when atoms share or transfer electrons to achieve a stable electron configuration. This sharing or transfer of electrons allows atoms to attain a lower energy state, making the molecule more stable. Chemical bonds can be covalent, where electrons are shared between atoms, or ionic, where electrons are transferred from one atom to another. These bonds are essential for the formation and stability of molecules and determine the physical and chemical properties of substances.

Sodium chloride (NaCl) and magnesium (Mg) are examples of network substances because they have a lattice structure in which the atoms are bonded together by strong ionic or metallic bonds. In a network substance, the atoms are arranged in a repeating pattern throughout the entire substance, resulting in a solid with high melting and boiling points. Sodium chloride is an ionic compound, where sodium ions and chloride ions are held together by electrostatic forces. Magnesium is a metallic element, and its atoms are bonded together by metallic bonds, which involve the sharing of electrons between atoms in a lattice structure.

A carbon atom with four single bonds forms a tetrahedral geometry. In this geometry, the carbon atom is at the center of a tetrahedron, with each of the four single bonds pointing towards the corners of the tetrahedron. This arrangement ensures that the bond angles between the carbon atom and its bonded atoms are approximately 109.5 degrees, resulting in a symmetrical and stable structure.

A carbon atom with a triple bond forms a linear geometry. This is because the triple bond consists of one sigma bond and two pi bonds, which results in a linear arrangement of the bonded atoms. In a linear geometry, the bonded atoms are in a straight line with an angle of 180 degrees between them. Therefore, the correct answer is linear.

In a chemical formula, subscripts are placed to the right of the chemical symbol, not to the left. Subscripts indicate the number of atoms of that type in a molecule.

Mass spectrometry is a technique used to determine the mass and structure of molecules, not the energy associated with their motions. It works by ionizing molecules and then separating them based on their mass-to-charge ratio. By measuring the mass of the ions, information about the molecular weight and composition can be obtained. However, it does not provide direct information about the energy associated with molecular motions, such as vibrational or rotational energies. Therefore, the statement is false.

Molecular substances do not melt at a very high temperature. In fact, they generally have lower melting points compared to other types of substances such as metallic or ionic compounds. This is because molecular substances are made up of individual molecules held together by weak intermolecular forces, which are easily overcome at lower temperatures. Therefore, the statement that molecular substances melt at a very high temperature is false.

Extended or network substances refer to substances that have a three-dimensional structure formed by the repeating arrangement of atoms or ions. Salts and metals have this type of structural organization, where the atoms or ions are held together by strong metallic or ionic bonds, forming a lattice-like structure that extends throughout the substance. This structure gives these substances their characteristic properties, such as high melting and boiling points, conductivity of electricity, and brittleness in the case of salts.

The question asks for the option that is not a compound. A compound is a substance made up of two or more different elements chemically combined. Sulfur dioxide, nitrous oxide, water molecule, and rust are all compounds because they consist of multiple elements. Oxygen molecule, on the other hand, is not a compound because it is made up of only one element, oxygen. Therefore, the correct answer is oxygen molecule.