Organizing The Element True And False Multiple Choice 10/28/10

Explanation
Mendeleev actually arranged the elements in his periodic table in order of atomic mass, not atomic number. The concept of atomic number was not yet known during Mendeleev's time. It was later discovered and developed by Henry Moseley in 1913. Therefore, it is never true that Mendeleev arranged the elements in order of atomic number.

Explanation
The statement "There are six periods in a periodic table" is never true. A periodic table consists of seven periods, which are horizontal rows that categorize elements based on their electron configurations. Each period represents a different energy level or shell. Therefore, the statement is incorrect as there are more than six periods in a periodic table.

Explanation
The statement "Most of the elements in the periodic table are metals" is always true. This is because the majority of elements in the periodic table are classified as metals. Metals are characterized by their ability to conduct heat and electricity, their malleability, and their shiny appearance. They are found on the left side and in the middle of the periodic table, occupying a large portion of the elements. Non-metals and metalloids make up the smaller portion of elements in the periodic table. Therefore, it can be concluded that the statement is always true.

Explanation
The statement that "The elements within a period have similar properties" is never true. In the periodic table, a period is a horizontal row that consists of elements with increasing atomic numbers. While elements within a period may have some similarities, such as having the same number of electron shells, their properties vary significantly. Elements within a period can have different chemical reactivity, physical states, and other properties due to variations in their atomic structure and electron configurations. Therefore, it is incorrect to say that elements within a period always have similar properties.

Explanation
Metals are good conductors of heat and electric current because of their unique atomic structure. They have a high density of free electrons that are able to move freely within the metal lattice. This allows for the efficient transfer of heat and the flow of electric current. In contrast, nonmetals have a lower density of free electrons and are poor conductors of heat and electricity. Metalloids, on the other hand, have properties that are intermediate between metals and nonmetals, and their ability to conduct heat and electricity can vary depending on the specific metalloid.

Explanation
The horizontal rows of the periodic table are called periods. Each period represents a different energy level or shell in which the elements' electrons are arranged. The number of periods in the periodic table corresponds to the maximum number of electrons that can occupy each energy level. The periods are numbered from 1 to 7, with each subsequent period having a higher energy level than the previous one. Elements within the same period generally have similar properties as they have the same number of occupied energy levels.

Explanation
The given answer "group" is correct because a group is a vertical column of elements in the periodic table. In the periodic table, elements are organized into groups based on similar properties and characteristics. Each group contains elements with the same number of valence electrons, which influences their chemical behavior. Therefore, a vertical column in the periodic table is referred to as a group. The other given terms, luster and solid, are not applicable to describe a vertical column of elements in the periodic table.

Explanation
Nonmetals are poor conductors of heat and electric current. This is because nonmetals have a high electrical resistance, which means they do not allow the flow of electric current easily. Additionally, nonmetals do not have free electrons that can carry heat energy, leading to their poor conductivity of heat. In contrast, metals are good conductors of heat and electric current due to their low electrical resistance and abundance of free electrons. Metalloids, on the other hand, have properties that are intermediate between metals and nonmetals and can exhibit varying degrees of conductivity.

Explanation
Metalloids are elements that have properties that are similar to both metals and nonmetals. They exhibit characteristics of metals such as being good conductors of electricity and having metallic luster, while also displaying nonmetallic properties like being brittle and having lower melting points. Metalloids are located along the staircase line on the periodic table, separating metals from nonmetals. They include elements such as boron, silicon, germanium, arsenic, antimony, and tellurium.

Explanation
Nitrogen is a nonmetal. Nonmetals are elements that lack metallic properties such as luster, malleability, and electrical conductivity. Nitrogen is a diatomic molecule, meaning it exists as N2 in its natural state. It is a colorless and odorless gas that makes up about 78% of the Earth's atmosphere. Nitrogen is an essential element for living organisms and is commonly found in compounds such as proteins and nucleic acids.

Explanation
Phosphorus is classified as a nonmetal because it is a brittle, solid element that lacks metallic properties like luster, malleability, and conductivity. Nonmetals tend to have lower melting and boiling points, and phosphorus is known for its low melting point of 44.1 degrees Celsius. Additionally, nonmetals generally have higher electronegativity values, and phosphorus has an electronegativity of 2.19. These characteristics make phosphorus fit the criteria for classification as a nonmetal.

Explanation
Arsenic is classified as a metalloid. Metalloids are elements that have properties of both metals and nonmetals. While arsenic is a solid at room temperature and has metallic luster, it is brittle and a poor conductor of heat and electricity, which are characteristics of nonmetals. Therefore, arsenic exhibits some properties of metals and some properties of nonmetals, making it a metalloid.

Explanation
Antimony is classified as a metalloid because it exhibits properties of both metals and nonmetals. It has a metallic luster and can conduct electricity, which are characteristics of metals. However, it is brittle and can form both metallic and nonmetallic compounds, which are properties of nonmetals. Therefore, antimony is considered to be a metalloid, falling in between metals and nonmetals on the periodic table.

Explanation
Bismuth is classified as a metal because it possesses the characteristics typically associated with metals. It is a solid at room temperature, has a shiny appearance, and is a good conductor of heat and electricity. Bismuth also has a high density and is malleable, meaning it can be easily shaped or molded. These properties align with the general properties of metals, thus categorizing bismuth as a metal.