Chemistry Topic 4 Quiz

Atoms of non-metal elements (except noble gases) obtain a stable electron arrangement like the noble gases by chemically joining with other non-metal atoms. The forces of attraction which hold these atoms together are called bonds. Bonds form when atoms share or transfer electrons to achieve a more stable electron configuration. These bonds can be covalent, where electrons are shared between atoms, or ionic, where electrons are transferred from one atom to another. Bonds are essential for the formation of compounds and the stability of molecules.

A compound is a substance that is formed when two or more different atoms chemically bond together. This means that the atoms are held together by chemical bonds, creating a new substance with different properties than the individual atoms. A compound can be made up of atoms from different elements, such as water (H2O) which is made up of hydrogen and oxygen atoms. Therefore, the correct answer is "A substance made of two or more different atoms chemically joined together."

The correct answer is that Mon- means 1, Di- means 2, Tri- means 3, and Tetra- means 4. This is because the prefixes in question are commonly used in numerical terms to indicate the number of something. Mon- is derived from the Latin word "monos" meaning "one," Di- is derived from the Greek word "di" meaning "two," Tri- is derived from the Latin word "tres" meaning "three," and Tetra- is derived from the Greek word "tetra" meaning "four." Therefore, each prefix corresponds to the numerical value stated in the correct answer.

The symbols in a formula represent the different elements present in the molecule. Each element is represented by a unique symbol, such as H for hydrogen or O for oxygen. By looking at the symbols in a formula, one can determine which elements are present in the molecule and in what ratio they are combined. The symbols provide information about the composition of the molecule and help in understanding its chemical properties.

The numbers in a formula indicate the amount of each element present in the molecule. These numbers, known as subscripts, represent the ratio of atoms of each element in the compound. For example, in the formula H2O, the subscript 2 indicates that there are two hydrogen atoms for every one oxygen atom. Therefore, the numbers in a formula provide information about the composition and proportion of elements in the molecule.

The correct answer is "A substance made of only one type of atom." An element is a pure substance that consists of only one type of atom. Each element is characterized by its unique atomic number, which represents the number of protons in the nucleus of its atoms. Elements are the building blocks of all matter and cannot be broken down into simpler substances by chemical means. They are represented by symbols on the periodic table, such as H for hydrogen and O for oxygen.

A covalent bond is formed when two non-metal atoms share a pair of electrons. This type of bond occurs when both atoms have a high electronegativity and are able to attract and share electrons. The sharing of electrons allows both atoms to achieve a more stable electron configuration, filling their outermost energy levels. This sharing of electrons creates a strong bond between the atoms, resulting in the formation of a covalent compound.

A double bond is formed when two pairs of electrons are shared between two atoms. This means that each atom contributes two electrons to the bond, resulting in a total of four electrons being shared. This type of bond is typically stronger than a single bond, as it involves a greater sharing of electrons between the atoms. Double bonds are commonly found in molecules such as carbon dioxide (CO2) and ethene (C2H4), where the atoms involved require additional electron sharing to achieve a stable configuration.

Hydrogen is a diatomic element because it exists naturally as a molecule consisting of two hydrogen atoms bonded together (H2). It is the simplest and most abundant element in the universe. Calcium, gold, and phosphorus are not diatomic elements as they exist in nature as single atoms or in different molecular forms.

The nucleus, located at the center of an atom, has a positive charge. This is because the nucleus is composed of positively charged protons and neutral neutrons. The protons carry a positive charge, while the neutrons have no charge. The overall positive charge of the protons in the nucleus is balanced by the negatively charged electrons that orbit around the nucleus, resulting in a neutral charge for the entire atom.

Each atom of a noble gas has a full outer energy level, which means that it has the maximum number of electrons allowed in that level. This makes noble gases stable and unreactive. However, the question also states that the outer energy level of a noble gas is empty. This is because the outermost energy level, also known as the valence shell, does not contain any electrons in noble gases since they have already achieved a stable electron configuration.

The shape of the molecule is called tetrahedral because it has four bonded atoms and no lone pairs of electrons. In a tetrahedral shape, the bonded atoms are arranged symmetrically around the central atom, forming a three-dimensional shape resembling a pyramid with a triangular base. This shape is commonly found in molecules with four bonding pairs and no lone pairs, such as methane (CH4) or carbon tetrafluoride (CF4).

Noble gases are different from other non-metal elements because they do not exist as molecules, but as single atoms. Unlike most non-metals, noble gases have full valence electron shells, making them stable and unreactive. This is why they are also known as inert gases.