Question
Fill in the Blank Question A horizontal row of elements in the modern periodic table is called a/an square Need help? Review these concept resources, Read About the Concept
Answer
4.7
(216 Votes)
Norma
Veteran · Tutor for 9 years
Answer
period
Explanation
In the modern periodic table, elements are arranged in a series of rows and columns based on increasing atomic number. The horizontal rows specifically are known as periods. Each period starts with an element having one electron in a new shell and ends with a noble gas, an element with a full shell of electrons. As you move from left to right across a period, the atomic number increases by one for each subsequent element, indicating an addition of one more proton in the nucleus and one more electron in the electron shells. This arrangement reflects the repeating pattern of chemical properties among the elements as their atomic numbers increase.