Why are the periods in the periodic table periodic?

Answer 1

The layout of the Periodic Table demonstrates recurring ("periodic") chemical properties. Elements are listed in order of increasing atomic number (i.e. the number of protons in the atomic nucleus). Rows are arranged so that elements with similar properties fall into the same vertical columns ("groups"). According to quantum mechanical theories of electron configuration within atoms, each horizontal row ("period") in the table corresponded to the filling of a quantum shell of electrons. There are progressively longer periods further down the table, grouping the elements into s-, p-, d- and f-blocks to reflect their electron configuration.

In printed tables, each element is usually listed with its element symbol and atomic number; many versions of the table also list the element's Atomic Mass and other information, such as its abbreviated electron configuration, electronegativity and most common valence numbers.

Answer 2

The chemical properties of elements in the periodic table are similar to those elements in the same column (which, for example, is why all the halogens (17 / VIIA / 7A) behave similarly). Each period repeats the chemical properties of the above period according to column. However, most of the time, only electrons in the s and p shells affect chemical properties, because they form the valence shell of electrons, which is why periods behave the way they do even with the addition of the transition metals (introduction of the d orbitals) and the lathanide and actinide series (introduction of the f orbitals).

Answer 3

The periodic table looks the way it does because, it is arranged depending on the number of neutrons and electrons also the group that it's in. For example, gold has the number 79 next to it, so it means that it has 79 neutrons so its placed between platinum and Mercury. Hydrogen is first because it only has one neutron is the nucleus and one electron.

Answer 4

The Periodic table has horizantal rows, called periods, and vertical columns called groups. Each period and group of elements has specific properties that only the elements on that certain period or group have.

Answer 5

The modern periodic table was developed because there was a need to organise elements in a way elements can easily be found (on the table) and for periodic trends to be observed.

Answer 6

The periodic table is set up according to how many protons are included in the outer shell of an atom, and as to how many protons is needs to lose or gain to be balanced.