Chemistry Quiz: Periodic Classification Of Elements

Dobereiner's triad is a concept in chemistry that states that certain elements can be grouped in sets of three based on their similar properties. These elements have atomic weights that are close to each other and their properties show a pattern of progression. In this case, Li, Na, and K are grouped together because they have similar chemical properties, such as being highly reactive alkali metals and having one valence electron.

Elements in the same vertical group of the periodic table have the same number of valence electrons. Valence electrons are the outermost electrons in an atom's electron cloud and are responsible for the chemical behavior of the element. Elements in the same group have similar chemical properties because they have the same number of valence electrons, which determines how they interact with other atoms to form compounds. Therefore, the number of valence electrons is the correct answer for this question.

not-available-via-ai

The incorrect statement is "All the metals form acidic oxides." This is incorrect because metals generally form basic or amphoteric oxides, which means they can react with both acids and bases. Acidic oxides are typically formed by non-metals.

The given answer states that statements (i), (ii), and (iii) are incorrect. This means that the correct statements would be (iv) only. Therefore, the correct explanation is that the elements in the Modern Periodic Table are arranged on the basis of their increasing atomic number, not decreasing atomic number. Additionally, the elements are arranged based on their increasing atomic number, not their increasing atomic masses. Lastly, isotopes are not placed in adjoining groups in the Periodic Table.

Metalloids are elements that have properties of both metals and non-metals. They are considered borderline elements because they exhibit characteristics of both metallic and non-metallic elements. They can act as electron donors with non-metals and as electron acceptors with metals, which is known as their amphoteric behavior. Examples of metalloids include boron, silicon, and germanium. However, metalloids are not good conductors of heat and electricity compared to metals. They have intermediate conductivity, making them semiconductors.

The first ionization energy is the energy required to remove one valence electron from an atom in its ground state. Since the ionization energy is given as 736 kJ per mole of atoms, it means that each individual atom requires 736 kJ to remove one valence electron. Therefore, the element must have 2 valence electrons, as the energy required to remove both of them would be 2 times 736 kJ.

Electron affinity refers to the energy change that occurs when an electron is added to a neutral atom to form a negatively charged ion (anion). It is expressed in electron volts (eV), which is a unit of energy. The correct answer states that electron affinity causes energy to be absorbed, which is true. When an electron is added to an atom, energy is required to overcome the electrostatic repulsion between the negatively charged electron and the negatively charged nucleus. Therefore, electron affinity is associated with energy absorption rather than energy release.

Element C has the atomic number 18, which indicates that it belongs to the 3rd period of the periodic table. The ionization potential refers to the amount of energy required to remove an electron from an atom. Generally, ionization potential increases as you move across a period from left to right. Since element C has the highest atomic number among the given elements, it is likely to have the highest ionization potential. Therefore, element C is the correct answer.

Isotopes of an element have different atomic masses but the same atomic number. This means that they have the same number of protons in their nucleus but different numbers of neutrons. Isotopes may have slightly different physical properties due to their different atomic masses, but they have the same chemical properties because chemical reactions are determined by the number of protons and electrons in an atom, which remains the same for isotopes of the same element. Therefore, the correct characteristics of isotopes of an element are (ii), (iii), and (iv).

The p-block elements that are not representative elements are the ones in Group VIII-A. The representative elements are found in Groups I-A, IV-A, V-A, VI-A, and VII-A of the periodic table. Group VIII-A elements, also known as the noble gases, are not considered representative elements because they have full valence electron shells and do not readily form compounds with other elements.

The ionization energy is highest for f-electrons because they are the innermost electrons in an atom and are shielded by other electrons. This means that they experience a stronger attraction from the nucleus, making it more difficult to remove them. Additionally, f-electrons have a higher effective nuclear charge due to their position in the periodic table, further increasing their ionization energy.

Ba(OH)2 is the most basic hydroxide among the given options. This is because barium hydroxide (Ba(OH)2) is a strong base and dissociates completely in water to release more hydroxide ions (OH-) compared to the other hydroxides. The presence of more hydroxide ions increases the concentration of hydroxide ions in the solution, resulting in a higher pH and stronger basicity. Therefore, Ba(OH)2 is the most basic hydroxide among the options provided.

The correct order of decreasing first ionization energy is C > Be > B > Li. This means that carbon (C) has the highest first ionization energy, followed by beryllium (Be), boron (B), and lithium (Li) with the lowest first ionization energy. First ionization energy is the energy required to remove the outermost electron from an atom, and it generally increases from left to right across a period in the periodic table. In this case, carbon has the highest first ionization energy because it is located further to the right in the periodic table compared to the other elements.

The nonmetallic character of an element is determined by its ability to gain electrons and form negative ions. In general, nonmetallic character increases from left to right across a period and decreases down a group on the periodic table. In this case, F (fluorine) is the most nonmetallic element because it is located in the top right corner of the periodic table and has a high electronegativity. O (oxygen) is the next most nonmetallic element, followed by C (carbon), Be (beryllium), and Li (lithium). Therefore, the correct order of increasing nonmetallic character is F