Answer:
Elements having same valence electrons are placed in <u>same group.</u>
Explanation:
First, let's start with some basic concepts of modern periodic table:
1. Modern Periodic table : It is the arrangement of element in the increasing order of their atomic numbers
The Modern periodic table is divided into Periods and groups .
Periods : These are the horizontal rows. There are seven periods in the periodic table . Period 1 has 2 element. Period two and three has 8 elements , period 4 and 5 have 18 elements and the period 6 and 7 have 32 elements.
Same period have same number of atomic orbital(Shell)
Group : The group is the vertical columns . There are 18 groups in the modern periodic table.Those element which have same group number will also have same number of electron in their outermost shell. The number of electron in the outermost shell determines the valency of the element.
So, elements showing same valency are placed in same group.
All alkali are place in group 1 and have 1 valance electron in the outermost shell
Answer:
B 24 m west I belive that it is the answer
The pH = -log of hydrogen ion concentration
The more acid a solution is the higher is its concentration of H+ ions and the lower is its pH. Acids have a pH lower that 7.
To answer this problem, we need to count the electrons in the given configuration. The complete configuration is 1s2 2s2 2p6 3s2 3p6. There are 2+2+6+2+6 equal to 18 electrons. We find next the element with an atomic number of 18. That element is noble gas argon.
