Page 12 - E-Science Prep.2 2024-2025 t1 Unit1_Neat

Give reason: Bec. Difference in electronegativity
Water molecule is a is relativelyhigh.
polar molecule
Polarity of water is Bec. The difference in
higher thanthat of electronegativity between oxygen and
ammonia hydrogen is greater than that between
nitrogen and hydrogen.

Metallic and Non-metallic property

Elements in periodic table are classified into:

Metals Non-metals Metalloids Noble gases

Metals Non-metals

-They have less than 4 -They have more than 4
electrons in their outermost electronsin their outer most
energy level energy level
- During any chemical reaction,
-During any chemical atom of non-metal tends to gain
reaction,atom of metal tends electrons to complete its outermost
to lose the electrons . energy level.
- changes into - changes into Negative ion
Positive ion (carries number (carries number of -ve charges
of +vecharges equal to equal to number of gained
number of lost electrons) electrons)

2nd Prep. First Term 15 12