How Does Nature of Oxides of Elements Change on Going from Left to Right in a Period of the Periodic Table?

The physical and chemical properties of elements in the modern periodic table show a regular variation in the periods and groups of the periodic table. When moving from left to right in a period, several features of elements such as the number of valence electrons, valency, atom size, metallic character, chemical reactivity, and the type of oxides change. When moving from the top to the bottom of a group, these properties change as well. These characteristics of periodic table elements are examined in more detail below.

Periods

Periods are the horizontal rows of elements in a periodic table. In the long form of the periodic table, there are seven periods. The atomic numbers of the elements in the periodic table are consecutive. As illustrated below, each period has a distinct amount of elements.

• There are two elements in the first period. A “very short time” is how it’s described.
• There are eight elements in the second period. It’s referred to as a brief period.
• There are eight elements in the third period. It’s also known as a short period.
• There are 18 elements in the fourth period. It’s referred to as a long period.
• There are 18 elements in the fifth period. It’s referred to as a long period.
• There are 32 elements in the sixth period. It’s also called a long period.

The remaining elements are found in the seventh period. It is a work in progress. The number of elements in a period is determined by the maximum number of electrons that may be accommodated in the various shells of an atom.

Groups

Groups are the vertical columns in a periodic table. In the long form of the periodic table, there are 18 groups. The number of groupings varies from one to eighteen. The elements in a given group do not have consecutive atomic numbers. Group 1 is located on the left side of the periodic table, while group 18 is located on the right side.

The Modern Periodic Table

Various Characteristics of Periods and Groups

• Valence Electrons in the period- The number of valence electrons, or outermost electrons, in elements increases from 1 to 8 as a period progresses from left to right, though it increases from 1 to 2 in the first period.
• Valence Electrons in the group– The number of valence electrons in a group of elements in the periodic table is the same for all of the elements in that group. For instance, all elements in group 1 of the periodic table, such as lithium and sodium, contain one valence electron in each atom.
• Valency in the period- The valency of elements increases from 1 to 4 and then declines to zero as you move from left to right in each short period. The number of outermost electrons required by an element to achieve the closest noble gas configuration is known as valency.
• Valency in the group- All elements in a group have the same valency because the number of valence electrons that determine valency is the same. For example, group 1 elements such as lithium, sodium, and potassium all contain one valence electron, hence they all have the same valency of one.
• Size of atoms in the period- The size of atoms or atomic size decreases as one moves from left to right in a periodic table period. Since the atomic radius represents an atom’s size, it may be claimed that as one moves from left to right in a periodic table period, the atomic radius decreases.
• Size of atoms in the group- The size of atoms or atomic size increases as one moves down the periodic table in a group. For instance, when we go from top to bottom in group 1, the size of the atoms gradually rises from lithium to francium.
• Metallic Character in the period- The metallic character of elements decreases as one move from left to right over a period, but the non-metallic character increases. For example, the metallic character decreases from sodium to magnesium to aluminium in the third period, silicon is metalloid, while the non-metallic character increases from phosphorous to sulphur to chlorine.
• Metallic Character in the group- The metallic character of elements increases as one moves down the periodic table in groups. Every time we move down a group of the periodic table, one more electron shell is added, and the atom’s size increases. For example, the metallic character of lithium to francium increases as we proceed down in group 1 of the periodic table.
• Chemical Reactivity in the period- The chemical reactivity of the elements decreases and then increases as you move from left to right. For example, sodium is a relatively reactive element in the third period, while magnesium is less reactive and aluminium is still less reactive. In the third period, silicon is the least chemically reactive element. Phosphorus is now quite reactive, while sulphur is still reactive and chlorine is extremely reactive.
• Chemical Reactivity in the group- Metals’ chemical reactivity increases as they progress down the periodic table in groups. The chemical reactivity of non-metals decreases as they progress along with the periodic table.

Nature of Oxides Moving across a Period

The tendency to lose electrons decreases as a period progresses, and hence the metallic character decreases. Since non-metal oxides are acidic. As a result, the basic character decreases from left to right over time. As a result, as a period progresses from left to right, the basic nature of oxides decreases and the acidic nature of oxides increases. Let’s look at the third-period elements as an example.

Na	Mg	Al	Si	P	S	Cl
Highly Basic	Amphoteric					Highly Acidic

Sodium oxide is very basic in nature while magnesium oxide is comparatively less basic in the third period of the periodic table shown above. Aluminium and silicon oxides are naturally amphoteric. Phosphorous oxides are acidic, sulphur oxides are much more acidic, and chlorine oxides are extremely acidic. As a result, it can be stated that as the periodic table moves from left to right in the third period, the basic nature of element oxides decreases while the acidic nature of oxides increases.

The tendency to lose electrons decreases as a period progresses, and hence the metallic character decreases. Since non-metal oxides are acidic. As a result, basic character decreases as you move from left to right, whereas basic character increases as you move below due to an increase in metallic character.

Metals react with oxygen to form basic oxygen compounds. The majority of these compounds are ionic in nature. When groups 1, 2, and lanthanides react with dioxygen, they form basic oxygen compounds. A lot of energy is released during the synthesis of these molecules. Except for a few exceptions, these compounds readily react with water. When non-metals react with oxygen, they generate acidic oxide complexes linked together by covalent bonds. Acid anhydrides are another name for these chemicals. Except for some compounds that have high melting points and form large molecules, acid anhydrides have low melting and boiling points.

Nature of Oxides Moving across a Group

The electropositive property of the central atom of an oxide determines whether the oxide is acidic or basic in general. The oxide becomes more basic as the central atom becomes more electropositive, while the oxide becomes more acidic as the central atom becomes more electronegative.

As we all know, electronegativity is an element’s ability to attract electron pairs. As a result, because the electronegativity decreases down the group, the acidic character of the oxides “decreases down the group.” Similarly, more electropositive metals have more basic oxide in their natural state. When a non-metal is more electronegative, it has a higher concentration of acidic oxide in its natural state. Since the “distance between the nucleus and the valence shell electron increases as one moves down the group, electronegativity decreases. As a result of the explanation above, we can conclude that the basic character of a group increases from top to bottom.

Metal oxides have a basic character, whereas non-metal oxides have an acidic nature. This means that as you move down the periodic table, the basic character of oxides gets stronger and the acidic character gets weaker. As a result, the nature of element oxides does not change as one moves down the periodic table. Oxides of all elements in a group have the same nature. For example, all elements in group 1 form basic oxides, such as lithium, sodium, and potassium, but all elements in group 17 form acidic oxides, such as fluorine, chlorine, and bromine.

Sample Questions

Question 1: Name an element that would show similar chemical properties as sodium.

Answer:

Chemical properties are similar among elements belonging to the same group. Potassium would show similar chemical properties as sodium since both potassium and sodium belong to the same group.

Question 2: An element belongs to the second group of the periodic table, is it a metal or non-metal?

Answer:

The metallic character of elements decreases as one move from left to right over a period, but the non-metallic character increases This means that the elements at the left side of the periodic table are all metals. Since the given element belongs to the second group, so it belongs to the left side of the periodic table. Hence this element is a metal.

Question 3: The element with electronic configurations 2, 6 belong to which period?

Answer:

The number of shells in the electronic configuration of an element tells which period the element belongs to. The given electronic configuration 2, 6 has two shells, so the given element belongs to the second period.

Question 4: Which among the periods or groups have elements with consecutive atomic numbers?

Answer:

In the modern periodic table, the periods have elements with consecutive atomic numbers.

Question 5: Name two properties of elements that do not change on going down a group.

Answer:

All elements in a group have the same valency because the number of valence electrons that determine valency is the same. Also the nature of element oxides does not alter as one moves down the periodic table. Hence, the two properties that do not change on going down the group are the valency of elements and the nature of oxides.