Socho tumhare paas paanch dost hain: Li, Na, K, Rb, aur Cs. Inke paas ek ek toy hai jo yeh actually chahte nahi (yahi valence electron hai).
Li sabse chhota bachcha hai, apna toy khud ke sabse paas rakhta hai, lekin jab koi trade offer karta hai (jaise paani), toh woh itna excited ho jaata hai kyunki woh tiny hai aur log usse bahut pasand karte hain (high hydration). Toh chahe woh doosron se apna toy zyada tightly pakde, woh trade mein SABSE PEHLE deta hai!
Cs sabse bada bachcha hai, apna toy barely pakde hua hai—itna door hai body se ki bas gir jaata hai! Woh bina kisi acchi trade ke bhi de deta hai.
Ab yahan funny baat: Li itna chhota hai ki woh apne diagonal neighbour Mg (jo ek alag group mein hai) se zyada milta-julta hai apne family se! Jaise Li aur Mg dono tiny bachche hain jo same tarike se toys share karte hain, chahe Mg technically alag family se ho. Dono nitrogen se nafrat karte hain (isse pakad ke nitrides banate hain), dono sirf normal oxygen toys chahte hain (fancy peroxide wale nahi), aur inke carbonates garam karne par asaani se toot jaate hain.
Sabak? Chhota aur highly charged hona (jaise Li⁺) tumhe apni family se ALAG banata hai!
4.2.03-Ionic-vs-covalent-character — Li compounds ke liye Fajans' rules
2.5.04-Lattice-energy-Born-Haber-cycle — LiF insoluble kyun hai
5.3.02-Standard-reduction-potentials — Li ki reducing power explain ki gayi
6.1.05-Hydration-enthalpy — Tiny ions ki itni badi hydration energies kyun hoti hain
#flashcards/chemistry
Alkali metals ka electronic configuration pattern kya hai? :: Sabhi alkali metals mein outermost s-orbital mein ek electron hota hai (ns¹ configuration). Example: Na hai [Ne] 3s¹.
Group 1 mein neeche jaane par atomic radius kaise change hoti hai aur kyun?
Atomic radius group mein neeche jaane par badhti hai (Li < Na < K < Rb < Cs) kyunki har element ek naya electron shell add karta hai, nucleus se distance badhati hai. Shielding bhi badhti hai, effective nuclear pull kamzor hoti hai.
Potassium sodium se kam dense kyun hai?
Potassium mein atomic radius ka unusually bada jump hota hai (3rd se 4th shell). Volume increase, mass increase ko outpace kar deta hai, isliye density temporarily drop ho jaati hai. Yeh otherwise increasing density trend mein anomaly hai.
Group 1 mein ionization energy ka trend kya hai?
Ionization energy group mein neeche jaane par ghatti hai (Li > Na > K > Rb > Cs). Jab atomic size badhti hai, outermost electron nucleus se aur door hota hai aur badhte nuclear charge ke bawajood usse remove karna aasaan ho jaata hai.
Alkali metals kerosene mein kyun store kiye jaate hain?
Alkali metals hawa mein oxygen aur moisture ke saath vigorously react karte hain. Kerosene ek nonpolar hydrocarbon hai jo hawa aur paani se contact ko rokta hai, metals ko stable rakhta hai.
Sodium paani ke saath react karne par kya products banate hain?
2Na + 2H₂O → 2NaOH + H₂. Sodium hydroxide (ek strong base) aur hydrogen gas produce hote hain. Yeh reaction exothermic hai aur hydrogen ko ignite kar sakti hai.
Lithium sirf normal oxide kyun banata hai jabki potassium superoxide banata hai?
Chhota Li⁺ sirf chhote O²⁻ anions (Li₂O banakar) ko stabilize kar sakta hai. Bada K⁺ bade O₂⁻ superoxide anions (KO₂ banakar) ko stabilize kar sakta hai. Yeh lattice energy considerations ki wajah se hai—chhote cations ko stable crystal structures ke liye chhote anions chahiye.
Aqueous solution mein kaun sa alkali metal sabse strong reducing agent hai aur kyun?
Lithium sabse strong reducing agent hai (E° = -3.04 V) kyunki uska tiny Li⁺ ion bahut zyada high hydration enthalpy rakhta hai. Solvation se release hone wali energy uski high ionization energy ko overcompensate karti hai.
Lithium ki teen anomalous properties batao.
(1) Group 1 mein sabse zyada melting aur boiling points; (2) N₂ ke saath seedha nitride (Li₃N) banata hai, doosre alkali metals ke unlike; (3) Iske compounds (jaise LiCl) mein significant covalent character hota hai aur organic solvents mein dissolve hote hain.
Li aur Mg ke beech diagonal relationship kya hai?
Li (Group 1, Period 2) aur Mg (Group 2, Period 3) ki similar charge density (charge/radius ratio) hoti hai, jo unhe similar chemical properties deti hai: dono nitrides banate hain, garam karne par carbonates/hydroxides decompose karte hain, sirf normal oxides banate hain, aur inke compounds mein covalent character hota hai.
LiF ki solubility kam kyun hai jabki doosre alkali halides highly soluble hain?
LiF ki lattice energy bahut zyada hoti hai kyunki Li⁺ aur F⁻ dono bahut chhote ions hain. Crystal lattice mein strong electrostatic attraction hydration enthalpy se overcome nahi ho sakti, LiF sparingly soluble rehta hai.
Sodium kaun sa flame color produce karta hai aur kyun?
Sodium yellow flame produce karta hai. Jab garam kiya jaata hai, 3s¹ electron ek higher energy level par jump karta hai; jab wapas aata hai, toh yellow light (589 nm) emit karta hai jo sodium mein specific energy gap ko correspond karta hai.
Alkali metals ke melting points kam kyun hote hain?
Alkali metals mein weak metallic bonding hoti hai kyunki inke paas delocalized electron sea mein contribute karne ke liye sirf ek valence electron hota hai. Group mein neeche jaane par atomic size badhne par metallic bonding aur kamzor hoti hai, aur melting points ghatte hain.
Lithium aur nitrogen ki reaction likho.
6Li + N₂ → 2Li₃N. Lithium nitride banta hai. Yeh unique hai—doosre alkali metals ordinary temperatures par seedhe nitrogen se react nahi karte, N≡N triple bond ki stability aur inke bade ionic size ki wajah se.
Li₂CO₃ garam karne par decompose kyun ho jaata hai lekin Na₂CO₃ nahi?
Chhote Li⁺ ki high polarizing power hoti hai, jo CO₃²⁻ ke electron cloud ko distort karta hai, C-O bonds ko kamzor karta hai aur decomposition aasaan banata hai: Li₂CO₃ → Li₂O + CO₂. Bade Na⁺ ki polarizing power kam hoti hai, isliye Na₂CO₃ thermally stable hai.
