Metals, non-metals, metalloids — properties

1.4.4 · Chemistry › Periodic Table — First Look

Ek root cause

WHY "electron behaviour" sab kuch decide karta hai? Kyunki saari bulk properties is baat se aati hain ki electrons kaise move karte hain:

Agar electrons loosely held hain aur freely roam kar sakte hain → ek "sea of electrons" → electricity/heat conduct karta hai, shiny hai, bendable hai → metal.
Agar electrons fixed bonds mein locked hain → koi free carrier nahi → insulator, brittle, dull → non-metal.
Agar electrons half-free hain → thoda conduct karta hai, aur zyada jab garam ho → metalloid (semiconductor).

Figure — Metals, non-metals, metalloids — properties

Property list derive karna (memorise mat karo — reason karo!)

Observation	WHY (model se)
Electricity conduct karta hai	Free electrons voltage apply hone par drift karte hain.
Heat conduct karta hai	Free electrons solid ke across kinetic energy quickly carry karte hain.
Malleable & ductile	Ions ki layers ek doosre ke past slide karti hain; electron sea bas re-flow ho jaata hai, koi bond snap nahi hota.
Shiny (lustrous)	Free electrons light ko absorb aur re-emit karte hain.
+ ions / basic oxides banata hai	Electrons lose karta hai → cations; oxide + water → base.

Observation	WHY
Insulator	Koi free carrier nahi.
Brittle	Ek layer ko push karo aur like-charges/bonds clash karte hain → slide hone ki jagah shatters ho jaata hai.
Dull	Light reflect karne ke liye koi electron sea nahi.
− ions / acidic oxides banata hai	Electrons gain karta hai → anions; oxide + water → acid.

WHY semiconductors? Unke electrons almost free hain lekin conduct karne ke liye ek choti energy nudge (heat/light/doping) chahiye. Woh controllable "in-between" conduction exactly isliye hai kyunki Si aur Ge har computer chip chalate hain — yaad rakhne wala 80/20 fact.

Worked examples

Common mistakes (Inhe Steel-man karo!)

Active recall

Kaun si ek atomic tendency metal ko define karti hai?

Outer electrons ka easy loss (low ionisation energy).

Metallic character kaunsi quantity ke inversely proportional hota hai?

Ionisation energy.

Ek period ke across, metallic character kya karta hai aur kyun?

Ghatta hai — nuclear charge ↑, radius ↓, toh IE ↑ aur electron loss mushkil hota hai.

Ek group mein neeche, metallic character kya karta hai aur kyun?

Badhta hai — radius ↑ aur shielding ↑, toh IE ↓ aur electron loss aasaan hota hai.

Table par sabse zyada metallic element kahan hai (noble gases exclude karke)?

Bottom-left (jaise Cs/Fr).

Metalloids ke naam batao.

B, Si, Ge, As, Sb, Te (aur kabhi kabhi Po).

Metals electricity conduct kyun karte hain?

Delocalised electrons ka ek mobile "sea" voltage ke under drift karta hai.

Non-metals brittle kyun hote hain?

Fixed directional bonds; sliding layers repulsion/bond breakage cause karti hain, flow nahi hota.

Metal oxide + water se ___ milta hai; non-metal oxide + water se ___ milta hai.

Base ; acid.

Semiconductor ki conductivity temperature ke saath metal se kaise alag behave karti hai?

Semiconductor T ke saath badhta hai; metal T ke saath girta hai.

Graphite ek conducting non-metal kyun hai?

Har carbon mein ek delocalised electron ek partial electron sea banata hai.

Recall Feynman: ek 12-saal ke bacche ko explain karo

Imagine karo ki har atom ek baccha hai jo balloons (electrons) pakde hua hai. Metal bacche apne balloons loosely pakde hain — unhe bump karo aur balloons freely float karne lagte hain, toh "messages" (electricity) crowd mein zip karte hain, aur bacche bina kisi ko drop kiye shuffle kar sakte hain (bendable). Non-metal bacche apne balloons tight pakde hain, extra bhi snatch kar lete hain — kuch bhi freely float nahi karta, toh koi message nahi jaata (insulator), aur agar unhe dhakka do toh yeh trip karke scatter ho jaate hain (brittle). Metalloid bacche apne balloons sort of loosely pakde hain — yeh kuch chodenge sirf tab jab tum unhe warm karo (semiconductors — woh cheez jo computer chips bana hain). Ek rule — tum apna balloon kitni tightly pakde ho — sab kuch explain karta hai.

Connections

Ionisation Energy — metallic character ka root cause.
Electronegativity — non-metals ke liye mirror concept.
Periodic Trends — Atomic Radius — explain karta hai kyun IE change hoti hai.
Acidic and Basic Oxides — metal/non-metal split ka chemical consequence.
Electronic Configuration — decide karta hai ki kitne electrons lose/gain hote hain.
Semiconductors and Doping — woh technology jo metalloids se bani hai.