1.
What is the group name of helium?
Correct Answer
D. Noble gases
Explanation
The group name of helium is noble gases. Noble gases are a group of chemical elements that are characterized by their low reactivity and full outer electron shells. Helium is a noble gas because it has a full outer electron shell, making it stable and unreactive. Other elements in the noble gases group include neon, argon, krypton, xenon, and radon.
2.
What is the name of horizontal rows in the periodic table?
Correct Answer
B. Periods
Explanation
The correct answer is "periods". In the periodic table, the horizontal rows are called periods. Each period represents the energy levels or shells of an atom's electrons. As you move from left to right across a period, the atomic number increases, indicating the addition of one more proton and electron. The elements within a period have similar electron configurations and exhibit certain trends in their properties.
3.
What are the last two types of elements to be added to the Periodic Table?
Correct Answer
A. Halogens and noble gases
Explanation
The last two types of elements to be added to the Periodic Table are halogens and noble gases. Halogens are a group of elements that include fluorine, chlorine, bromine, iodine, and astatine. They are known for their high reactivity and ability to form compounds with other elements. Noble gases, on the other hand, are a group of elements that include helium, neon, argon, krypton, xenon, and radon. They are known for their low reactivity and stability, which is why they are often used in lighting and as inert gases.
4.
Which feature on the Periodic Table is used to identify an element?
Correct Answer
C. Atomic number
Explanation
The atomic number of an element is the number of protons in the nucleus of its atom. This number is unique to each element and serves as its identifying feature. It determines the element's position in the periodic table and provides information about its properties and behavior. Therefore, the atomic number is used to identify an element.
5.
Most of the elements on the periodic table are metals?
Correct Answer
A. True
Explanation
The statement is true because the majority of the elements on the periodic table are indeed metals. Metals are characterized by their ability to conduct electricity and heat, their malleability and ductility, and their shiny appearance. Examples of metals include iron, copper, gold, and aluminum. Nonmetals and metalloids make up the minority of elements on the periodic table.
6.
The atomic number of an element is same as the number of?
Correct Answer
B. Protons
Explanation
The atomic number of an element represents the number of protons in the nucleus of an atom. This number determines the element's identity and its position on the periodic table. Neutrons, on the other hand, contribute to the mass of the atom but do not affect its chemical properties or identity. Therefore, the correct answer is protons.
7.
What is the symbol for sodium?
Correct Answer
C. Na
Explanation
The correct answer is Na. Sodium is a chemical element with the symbol Na, derived from the Latin word "natrium." It is a highly reactive metal that is commonly found in compounds such as table salt (sodium chloride) and baking soda (sodium bicarbonate). The symbol Na is used to represent sodium in chemical equations and formulas.
8.
Sulfur is non-metal.
Correct Answer
A. True
Explanation
Sulfur is a non-metal because it is located on the right side of the periodic table, specifically in group 16. Non-metals generally have properties such as low melting and boiling points, poor conductivity of heat and electricity, and tend to gain electrons when forming compounds. Sulfur fits these characteristics, making the statement "Sulfur is non-metal" true.
9.
The sodium atom contains 11 electrons, 11 protons and 12 neutrons. What is the mass number of sodium?
Correct Answer
C. 23
Explanation
The mass number of an atom is the sum of its protons and neutrons. In this case, the sodium atom has 11 protons and 12 neutrons, so the mass number is 11 + 12 = 23.
10.
Which group contains elements that are the most reactive?
Correct Answer
B. Alkali metals
Explanation
The alkali metals group contains elements that are the most reactive. This is because alkali metals have only one valence electron, which they are eager to lose in order to achieve a stable electron configuration. This makes them highly reactive and prone to forming positive ions. In contrast, halogens are also reactive but tend to gain electrons to achieve a stable electron configuration. Noble gases, on the other hand, have a full valence electron shell and are therefore the least reactive group of elements. Alkaline earth metals are less reactive than alkali metals, but still more reactive than halogens and noble gases.