Все изотопы одного элемента имеют одинаковый заряд ядра. Обычно изотоп обозначается символом химического элемента, к которому он относится, с добавлением верхнего левого индекса, например, 12 C, 222 Rn. Все изотопы одного элемента имеют одинаковый заряд ядра, отличаясь лишь числом нейтронов. Обычно изотоп обозначается символом химического элемента, к которому он относится, с добавлением верхнего левого индекса, означающего массовое число (например, 12C, 222Rn).
Обьяснение:
Пример:
Углерод.Изотоп 12C называется легким, 13C тяжелым, а 14C радиогенным.
A student smart card is a very useful tool, controlled by electronic systems, that can be used in a lot of different ways. It can be used by students, as well as staff members to access college buildings and ensure the facility's safety as only cardholders will be able to enter. The same goes for other places such as libraries (you can either use it to enter the library itself or, for example, borrow and return books) and any kind of accommodation (dormitories in our case). Another usage the smart card has is that similar to what we use our credit cards for - cashless payment. You can use it to pay for anything you can find on campus: make photocopies or scan and print out documents, buy food and drinks from vending machines or order favourite dishes at any available catering facility and use your smart card to pay for it. As you can see, opportuinities are endless and make student life much more comfortable and accessible.
1. boarding school f. pupils live and study here
2. coeducational h. boys and girls study together
3. comprehensive school i. takes pupils of all abilities
4. compulsory g. required by law
5. further education b. education for people who are older than school age
6. infant school j. a school for children from 5 to 7 years old
7. junior school e. a school for children from 7 to 11
8. nursery school a. a school for children from 2 to 5 years old
9. private school d. parents pay for this school
10. state school c. education here is free of charge