কার্বন ডাই অক্সাইডে কার্বনের যোজনী ৪ কেন?

 যোজনী: কোনো মৌল যতটি অক্সিজেন পরমানুর সাথে যুক্ত হয় তার সংখ্যাকে দ্বিগুণ করলে ঐ মৌলের যোজনী পাওয়া যায়। 

কার্বন পরমাণু ২টি অক্সিজেন পরমাণুর সাথে যুক্ত হয়।তাই সহজ কথায় কার্বন পরমাণুর যোজনী ২×২=৪।

অন্যভাবে,

যোজনী হলো কোনো পরমাণুর শেষ কক্ষপথে বিজোড় ইলেক্ট্রন সংখ্যা।

Cএর ইলেকট্রন বিন্যাস:

1s^2 2s^2 2px^1 2py^1 2pz^0

এখানে ২ নং অরবটালে ২টি বিজোড় ইলেকট্রন বিদ্যমান(2px^1 2py^1)।তাই স্বাভাবিক অবস্থায় কার্বন এর যোজনী 2।

কিন্তু উত্তেজিত (excited) অবস্থায় কার্বন এর ইলেক্ট্রন বিন্যাস :

C(6):1s22s12px12py12pz1C(6):1s22s12px12py12pz1.

এখানে বিজোড় ইলেকট্রন 4 টি।তাই যোজনী ও 4।

(CO2 গঠনের সময় C excited অবস্থায় থাকে)।

SSC 2022 8th Week Assignment Physics

শিক্ষার্থী বন্ধুরা,

আজকে আমি তোমাদের অষ্টম সপ্তাহের ফিজিক্স অ্যাসাইনমেন্টের উত্তর প্রদান করব।তোমরা উত্তর পত্র থেকে শুধু ধারণা নিয়ে নিজেদের মত লিখবে।দয়া করে উত্তরটি হুবহু কপি করবে না।

প্রশ্ন :

উত্তর :

A Rickshaw Puller Paragraph [470 words] ||For JSC,SSC,HSC||

 The man who earns his livelihood by pulling rickshaw is called a rickshaw puller. Being a man of little education he is, so to speak, a poor day labourer. Generally he is seen in the street. He carries passengers and goods from one place to another on payment. He hires a rickshaw from the owner on a daily basis. They have to give fixed amounts to the owner of the rickshaw everyday. He has to give the amount even when he is not well or earns nothing during the day . There are a few who pull their own rickshaws. A rickshaw puller is basically very poor. He can hardly afford to live in a good house. So, he lives in the slum to minimize his living cost. A rickshaw puller is dressed poorly. Sometimes his clothes are torn. A rickshaw puller works from dawn to midnight, but his income is so meagre . He maintains his familý with his meagre income. As a result, he has to lead a miserable life. A rickshaw puller usually depends on his daily income to maintain his family. He has no other source of income. Moreover, due to ignorance He maintains a large family with his limited income. A rickshaw puller is seen sitting idly in hos rickshaw of sleeping in his rickshaw beside a tree.He pulls the rickshaw in scorching sun, at chill winter nights and even in heavy rains. A rickshaw puller demands more when the weather is foul.Sometimes they try to cheat with the passengers. They try to take undue advantage of the ignorance or innocence of the people. They especially cheat the foreigners who are not familiar with the local system. However most often they are cheated by the passengers.Some passengers are not ready to pay him reasonable price. They create scene and try to take undue advantage. Moreover, a rickshaw puller has to work very hard ignoring the severe heat of the sun or rain. The work of a rickshaw puller is very risky in a busy town where numerous buses, trucks and cars run all day long. He has to ride his rickshaw very carefully all the time. Sometime they also bargain with the passengers and even misbehave with them. But generally they behave very gently with the passengers. He cannot pull his rickshaw when he falls sick. The day he fails to pull his rickshaw, he has no income that day. In these cases, he suffers most. Sometimes, he along with the members of his family have to starve. A rickshaw pullers life is full of sorrows and sufferings.He can hardly enjoy peace and happiness.By chance,if he can earn more Than his hope,than his joy knew no bound.In these cases he can enjoy good foods.But this good luck is very infrequent in his life.