BBC Bitesize - GCSE Chemistry (Single Science) - Groups and periods - Revision 1
Groups are columns of elements, while periods are rows of elements. Xe ( same number of elements as period 4, same general structure, and. Elements that are in the same period have chemical properties that are not all that similar. Consider the first two members of period 3: sodium (Na) and. Elements in the same period have the same number of electron shells; moving . be understood in relation to the types of forces holding the elements together.
The chemical behavior of atoms is controlled by their electron configuration. Since the families of elements were organized by their chemical behavior, it is predictable that the individual members of each chemical family will have similar electron configurations. Families of the Periodic Table Remember that Mendeleev arranged the periodic table so that elements with the most similar properties were placed in the same group. All of the 1A elements have one valence electron.
This is what causes these elements to react in the same ways as the other members of the family. The elements in 1A are all very reactive and form compounds in the same ratios with similar properties with other elements.
Because of their similarities in their chemical properties, Mendeleev put these elements into the same group. Although most metals tend to be very hard, these metals are actually soft and can be easily cut. Once again, because of their similarities in electron configurations, these elements have similar properties to each other.
The same pattern is true of other groups on the periodic table. Remember, Mendeleev arranged the table so that elements with the most similar properties were in the same group on the periodic table. It is important to recognize a couple of other important groups on the periodic table by their group name. This group contains very reactive nonmetal elements.
Families and Periods of the Periodic Table - Chemistry LibreTexts
These elements also have similar properties to each other, the most significant property being that they are extremely unreactive, rarely forming compounds.
We will learn the reason for this later, when we discuss how compounds form.
All of the elements in the second row the second period have two orbitals for their electrons. As you move down the table, every row adds an orbital. At this time, there is a maximum of seven electron orbitals.
Groups and periods
The periodic table also has a special name for its vertical columns. Each column is called a group. The elements in each group have the same number of electrons in the outer orbital. Those outer electrons are also called valence electrons.
They are the electrons involved in chemical bonds with other elements. Every element in the first column group one has one electron in its outer shell. Every element in the second column group two has two electrons in the outer shell. As you keep counting the columns, you'll know how many electrons are in the outer shell.
There are exceptions to the order when you look at the transition elementsbut you get the general idea.
Period (periodic table) - Wikipedia
Transition elements add electrons to the second-to-last orbital. For example, nitrogen N has the atomic number seven. The atomic number tells you there are seven electrons in a neutral atom of nitrogen.
How many electrons are in its outer orbital? Nitrogen is in the fifteenth column, labelled 'Group VA'.
- Elements as Building Blocks
- 2.3: Families and Periods of the Periodic Table
- Period (periodic table)
The 'V' is the Roman numeral for five and represents the number of electrons in the outer orbital. All of that information tells you there are two electrons in the first orbital and five in the second Phosphorus P is also in Group VA which means it also has five electrons in its outer orbital.