Page 13 - E-Science Prep.2 2024-2025 t1 Unit1_Neat

Graduation of metallic property in the
modern periodic table:

Through periods:

-Each period starts with strong metal [in group 1 (lA)], where by
increasing the atomicnumber:

- The metallic property decreases till we reach metalloids.
- Then the nonmetallic property appears and increases till we reach the
strongest

Through Groups:

In metallic groups (groups which start with metal) :
The metallic property increases gradually as we go from top to bottom
as in group(lA) GR.
because as the atomic number increases the atomic size increases,
so the ability tolose the outermost electrons increases

So: Lithium (Li) is the lowest metallic element in group
(lA).

- Cesium (Cs) is the strongest metallic element in group (lA).

Cesium is considered as one of the strongest metallic
element in the M.P.T (Due to the largest size)

2nd Prep. First Term 16 13