Question

2. Periods are

that run from left to right
3. Elements in the same period have the same
Every element in the first period has
element in the second period has
pattern?
shell for its
for its
Every
See the
5. Groups are
that run from top to bottom.
6. The elements of a group have the same number of
shell.
in their
7. Every element in group one has
element in group two has
electron in its outer shell. Every
electrons in its outer shell.
8. Hydrogen is special because it can act like two groups,
and
9. Hydrogen sometimes is
electron.
an electron and sometimes it has an
electrons in its outer shell, it is grouped
10. Although helium has only
with elements that have
elements. They each
11. The green elements on this table are called
have two electrons in their outer shell.
​

Answer 1

Periods on the periodic table are horizontal rows that reflect the number of electron shells of elements, which range from 1 to 7. As you move across a period, the number of electrons increases. In contrast, groups are vertical columns where elements share the same number of valence electrons, leading to similar chemical properties.

Step-by-step explanation:

In the context of the periodic table, periods are horizontal rows that define the arrangement of elements. These periods range from left to right and are numbered 1 through 7, starting at the top of the table. Periods indicate the number of electron shells an element has, with each period beginning when a new principal energy level commences to fill with electrons. For instance, period 1 has only two elements: hydrogen and helium. Other periods have more elements, reflecting additional electrons filling the subsequent principal energy levels.

The elements within a period have the same number of electron shells, but as you move from left to right across the table, the number of electrons in the outer shell increases for the elements. This progression affects their chemical and physical properties. When it comes to groups, the vertical columns of the periodic table, elements in the same group have identical numbers of electrons in their valence shell, contributing to similar chemical behavior.

Answer 2

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Step-by-step explanation: