• Гідрологія і Гідрометрія
• Господарське право
• Економіка будівництва
• Економіка природокористування
• Економічна теорія
• Земельне право
• Історія України
• Кримінально виконавче право
• Медична радіологія
• Методи аналізу
• Міжнародне приватне право
• Міжнародний маркетинг
• Основи екології
• Предмет Політологія
• Соціальне страхування
• Технічні засоби організації дорожнього руху
• Товарознавство продовольчих товарів

SUPPLEMENTARY QUESTIONS

1.Write the names of the alkali metals with their symbols.

2.Why are alkali metals located in group 1A in the periodic table?

3.Why is it difficult to take the second electron from alkali metals?

4.Alkali metals cannot be found freely in nature.

a. What is the main reason? b. Write down briefly where sodium metal is found in nature.

Active metals. INTRODUCTION

The metals in group 2A are called alkaline earth metals. This group includes beryllium (Be), magnesium tMg),calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra). The word "earth" was used for the oxides of group 2A by the ancient scientists. They thought of these oxides as elements. In fact, magnesium, calcium, strontium and barium metals were first isolated from their oxides. Alkaline earth metals, after the alkali metals, are secondary metals with strong metallic properties. The group 2A elements are less active than those of 1A, whereas they are more active than those of group 3A. Except Be, all form ionic compounds. Be forms mostly covalent compounds. The electrons in their valence shell occupy the s orbitals. Therefore, by losing these electrons through a chemical change they easily gain +2 charge. In this group, beryllium has similar chemical properties with aluminum, and magnesium has similar chemical properties with lithium.

Читайте також:

1. A. Listen to James describing his family situation and answer the questions.
2. Add question-tags and give full answers to the questions.
3. Answer the following questions
4. Answer the following questions about the text.
5. Answer the following questions about yourself, your friends and your ideas about friendship.
6. Answer the following questions.
7. Answer the following questions.
8. Answer the following questions.
9. Answer the following review questions
10. Answer the questions
11. Answer the questions
12. Answer the questions about the pictures.

Переглядів: 389