Question

21 cach of which retains its separate properties, sa sact aes, h as salt water, and sus 2 Chemistry, Matter, and Life ns Water is a vital substar body and is needed as ance are the elements ths sovent osed of properties, i , chlorine le abourtsrn nd ox. It makes up more than half of the drogen, oxygen, carbon, and nitrogen sulfur, chlorine, and cote nd a Inorganie compounds r, whereas calcium, sodium, potassium. H) when dissolved in water. Bases can accept hydroxide ion (OH). The pli scale is hyu contain th eo e acids sur , bases, and salts. Acids are co water. Bases can accept (bind with release aan Acids are compounds that can release and usu account for most of the remaining ally contain the l base. Salts are formed babonds wn an acid reacts with a base. The compon ) hydrogen ions acid or The components of a salt are always joined umber. Isotopes that give off radiation by ionic bonds, med whena o strength of an a Isotopes are forms of e are said to be Beca re useful in diagnosi adioactive. Because they can penetrate tiss that vary in neutron is. Radioactive substances also can penetrate tissues and can be used in the treatment many ed in the rbohydrates, and lipids are the organic compdkourt traced in the body, they ol many typc types of have the ability to destroy tissues a t Each type of organic compound is of proteins. function as catalysts ound. Important molecules built f built frt rgiccounds characteristic of living organisms building blocks. Enzymes, an important rom ucleotides are a fourth type of organic n characteristic ype nucleotides include DNA, RNA, and AT Addressing the Learning Objectives 1. DEFINE A CHEMICAL ELEMENT. See Exercise 2-1. 2, DESCRIBE THE STRUCTURE OF AN ATOM. EXERCISE 2-1 Write the appropriate term in each blank from the list below Not all terms will be u nucleus proton element electron atom energy level neutron 1. A positively charged particle inside the atomic nucleus 2. The smallest complete unit of matter 3. An uncharged particle inside the atomic nucleus 4. A substance composed of one type of atom 5. The part of the atom containing protons and neutrons 6. A negatively charged particle outside the atomic nucleus

Answer 1

1. Chemical element is a substance that cannot be chemically interconverted or broken down into simpler substances and are primary constituents of matter.

2. Structure of atom

An atom is the smallest unit of matter that retains all of the chemical properties of an element. Atoms combine to form molecules, which then interact to form solids, gases, or liquids.
Atoms consist of three basic particles: protons, electrons, and neutrons. The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). The outermost regions of the atom are called electron shells and contain the electrons (negatively charged). Atoms have different properties based on the arrangement and number of their basic particles.

Exercise 2.1

1. Proton
2. Atom
3. Neutron
4. Element
5. Nucleus
6. Electron