dhaatu

'dhaatu' ke anya arthon ke liye dekhein - dhaatu (bahuviklpi)

dhaatueain - maanav sabhyata ke poore itihaas mein sarvaadhik prayukt padaarthon mein dhaatueain bhi hain

luhaar dvaara dhaatu ko garm karne par

rasaayanashaastr ke anusaar dhaatu (metals) ve tatv hain jo saralata se ilektraan tyaag kar dhanaayan banaate hain aur dhaatuon ke paramaanuon ke saath dhaatvik bandh banaate hain. ilektraanik model ke aadhaar par, dhaatu ilektraanon dvaara aachhaadit dhanaayanon ka ek laitis hain.

dhaatuon ki paaramparik paribhaasha unke baahya gunon ke aadhaar par di jaati hai. saamaanyat: dhaatu chamakeele, pratyaasth, aaghaatavardhaneeya aur sugadh hote hain. dhaatu ushma aur vidyut ke achhe chaalak hote hain jabki adhaatu saamaanyat: bhangur, chamakaheen aur vidyut tatha ooshma ke kuchaalak hote hain.

raasaayanik tatvon ko sarvapratham dhaatuon aur adhaatuon mein vibhaajit kiya gaya, yadyapi donon samoohon ko bilkul pruthak‌ naheen kiya ja sakta tha. dhaatu ki paribhaasha karna kathin kaarya hai. mote roop se ham kah sakte hain ki yadi kisi tatv mein nimnalikhit sampoorn ya kuchh gun hon to use dhaatu kaheinge :

(1) chamak,

(2) paraandhata,

(3) saadhaaran taap par thos,

(4) svachh satah dvaara prakaash ke paraavartan (Reflection) ka gun,

(5) ooshma evam vidyut‌ ki uttam chaalakata, evam

(6) drav avastha se thannda karne par kristal roop mein thos padaarth ka banana.

ham yeh avashya kah sakte hain ki yadi koi tatv vishuddh avastha mein chamakadaar aur vidyut‌ ka chaalak naheen hai, to vah adhaatu (non-metal) hai. prakruti mein asanyukt avastha mein birli dhaatu hi milti hai. svarn, rajat, plaitinm aur kabhi-kabhi taamr dhaatueain yadaakada mil jaati hain. adhikaansh dhaatuon ke ayask (Ores) milte hain jo adhaatuon (jaise okseejan, kaarban, gandhak aadi) ke saath dhaatuon ke yaugik hote hain. ye yaugik bhi shuddh avastha mein na hokar anya khanij mein mishrit rahate hain. in ayaskon se vividh reetiyon dvaara dhaatueain nikaali jaati hain.

dhaatu praay: rasaayanik roop se kriyaasheel hote hain. hava mein aakseejan se sanyog kar dhaatvik aaksaaid banaate hain. sabse jyaada kriyaasheel alkali dhaatu (sodiym, leethiym, poteshiym - varg I ke dhaatu) hote hai jabki uske baad alkali mruda dhaatuon (baireliym, maigneshiym, kailshiym - varg II ke dhaatu) ka sthaan aata hai. udaaharanaarth -

4Na + O₂ → 2Na₂O (sodiym oksaaid)

2Ca + O₂ → 2CaO (kailshiym oksaaid)

4Al + 3O₂ → 2Al₂O₃ (alyoomeeniym oksaaid)

sankraman dhaatuon ka okseekaran apekshaakrut dheere se hota hai. dhaatvik aaksaaid dhaatu ke upar ek parat bana lete hain, jaise - lohe mein jang lagana. dhaatvik oksaaid kshaareeya hote hain jabki adhaatvik oksaaid pradhaanataya amleeya.

hailojanon se abhikriya karte dhaatu dhaatvik hailaaid lavan banaate hain. udaaharanaarth -

2Na + Cl₂ → 2NaCl (sodiym kloraaid - saadhaaran namak)

Ca + Cl₂ → CaCl₂ (kailshiym kloraaid)

2Li + F₂ → 2LiF (leethiym floraaid)

adhik kriyaasheel dhaatu jal ke saath abhikriya karke kshaar banaate hain aur haaidrojan gas mukt karte hain.

2Na + 2H₂O → 2NaOH + H₂

kam kriyaasheel dhaatu saadhaaran taap par jal se abhikriya naheen karte balki ve tapt avastha mein bhaap se abhikriya karke dhaatvik oksaaid banaate hain.

Mg + H₂O → MgO + H₂

Zn + H₂O → ZnO + H₂

amlon se abhikriya karke dhaatu lavan banaate hain aur haaidrojan gas mukt karte hain -

Mg + H₂SO₄ → MgSO₄ + H₂

dhaatu aaghaatavardhaneeyata\aaghaatavardhaneeya hote hain - inko hathaude se peetakar lamba kiya ja sakta hai. jaise kisi alyoominiym ya taanbe ke taar ko par prahaar (aaghaat) karan se usaka prasaar (vardhan) hota hai. dhaatu tanya bhi hote hain, yaani unhein kheenchakar ek lamba taar banaaya ja sakta hai. adhaatuon mein yeh gun naheen paaya jaata hai. udaaharanaarth faasforas ko kitna bhi kheenchne par vo lambe taar ke roop mein naheen banaaya ja sakta. dhaatuon ka ghanatv bhi uchch hota hai tatha inmein ek vishesh prakaar ki chamak hoti hai jise 'dhaatvik chamak' kehte hain.

adhiktar dhaatueain bhoore shvet se lekar chamakadaar shvet rang ki hoti hain. svarn aur taamr iske apavaad hain. paarad ko chhodkar (galanaank -38.87 sein.) aur saare dhaatu saadhaaran taap par thos hain. seejiym tatha gailiym dhaatu ka galanaank kramash: 28° sein. tatha 29.78° sein. hain. doosari aur tangsten dhaatu 3,380° sein. par drav banti hai. uchch taap par dhaatueain vaashp mein parivrtit ho jaaeaingi. par ismein bhi unamein koi samaanata naheen dikhaai deti. paarad ka kvathanaank 356° sein. hai, parantu tangsten ka 5,930° sein.. aisa anumaan hai ki taintelam 6,100° sein. par vaashpit hoga.

yadi ham vidyut-chaalakata par dhyaan dein, to gyaat hoga ki adhaatuon ke vipreet dhaatueain uttam chaalak hain. dhaatuon mein sabse shreshth vidyuchchaalak rajat hai. yadi tulana ke liye usaki chaalakata 100 maan li jaae to kuchh anya saadhaaran dhaatuon ki chaalakata nimnalikhit saarani ke anusaar hogi-

is maap par bauraun (adhaatu) ki chaalakata 10^-10 aaegi. isi prakaar dhaatueain uttam ooshma chaalak bhi hoti hain. visheshakar vishuddh dhaatuon ki donon chaalakataaeain lagbhag ek kram mein rahati hain. taap ghataane par dhaatuon ka vidyutpratirodh ghatata hai, athva ham yeh bhi kah sakte hain ki chaalakata badhti hai.

dhaatuon ka taap badhne par unka aakaar badh jaata hai. is gun ko taapeeya prasaar (Thermal expansion) kehte hain. tharmaameetar mein paarad ke isi gun ka laabh uthaaya jaata hai. kuchh aisi mishradhaatueain bhi bani hain jinka taap ke saath taapeeya prasaar ati sookshm hai.

lauh, nikel aur kobaalt ko chhodkar anya dhaatuon mein chunbakeeya gun anupasthit hai.

dhaatu mein apna aakaar rakhane ki badi kshamata hoti hai. is or yeh baahari dabaav ka bahut pratirodh karta hai. mainganeej sabse kathor dhaatu hai aur leethiym sabse komal. tanaavakshamata mein tangsten sabse shreshth aur seesa bahut nyoon hai.

anek dhaatuon mein ghaatuvardhyata (malleability) aur tanyata (ductility) ke gun hote hain. inhein thok peetakar patali part banaai ja sakti hai (visheshakar svarn, rajat aur taamr ki). tanyata ke falasvaroop yadi kisi patale chhidr ke madhya se unhein kheencha jaae to unke patale taar khinch aaeainge.

dhaatu kristaleeya hoti hain jo adhiktar dhan pranaali ke hote hain. dhaatu ke parmaanu dhan ke aakaar mein susajjit hone ke kaaran isi shreni ke kristal banaate hain. kuchh dhaatueain shadfalakeeya (Hexagonal) pranaali ke manibh banaati hain. kabhi kabhi ek hi dhaatu ke parmaanu ek se adhik pranaali mein vyavasthit hokar vibhinn roop mein kristal banaate hain. inhein apararoopata (Allotropic modification ya Allotropy) kaheinge.

dhaatu ke parmaanu ilektraunadaata hote hain. kristal mein inke dhanaayan niyat sthaan mein raheinge aur mukt ilektraun uske rikt sthaanon mein. is prakaar yeh ilektraun svatantr aur sachal raheinge, jiske kaaran dhaatu mein uchch chaalakata, paraavartakata (reflectivity) aadi gun aa jaate hain.

dhaatuon ke lagbhag sabhi gun unki parmaanu sankhya ke aabart falan (Periodic function) hote hain. yeh aavartita parmaanu aayatan vidyut‌ aur ooshma chaalakata, ghaatavardhyata, tanyata, sangalan ki gupt ooshma (Latent heat of fusion) aadi mein ullekhaneeya hain. laader maayar ne isi aavartita ki or vaigyaaniko ka dhyaan pehle pahal tatvon ki aavartasaarani dvaara aakarshit kiya tha.

ayaskon se dhaatu ke nishkaashan aur upayog mein laane ke poorv unke shuddheekaran ki prakriya ko dhaatukarm kehte hain^[1].

1. ↑ Singh, avadhesh Kumar; sinha, anil Kumar (1996), haai school rasaayan shaastr (truteeya san॰), bhaarati bhavan, pa॰ 53, aai॰aऍsa॰abee॰aऍna॰ 81-7709-090-9

• adhaatu
• mishradhaatu