Question

1. Which of the following is not among the first twenty elements? A. Chlorine B. Beryllium C. Iron D. Calcium 2. The number of atoms in one mole of an element is referred to as A. molecularity B. chemical symbol C. atomicity D. chemical element 3. What is the chemical symbol of Aluminum? A. AL B. Al C. aL D. al. 4. Which of the following is a heterogeneous mixture? A. Soft drink B. Air C. Flood C. Solution salt 5. Which of the following is false about mixtures? A. They can easily be separated by Chemical method B. They are not represented by chemical formula C. They can be homogenous or heterogeneous D. The constituents are physically combined 6. Which of the following elements is diatomic? A. Sodium B. Potassium C. Helium D. Oxygen 7. A diatomic element has ___________ number of atoms in one molecule of its element. A. one. B. two. C. three. D. four. 8. Which of the following is an example of a colloidal solution? A. Chalk in water B. Sand in water C. Sugar solution D. Solution of eggwhite 9. A mixture whose constituents are uniformly mixed is referred to as a A. homogeneous mixture B. suspension C. heterogeneous mixture D. colloidal solution 10. _____________ is a force that opposes motion when two surfaces are in contact with each other. A. Movement B. Pressure C. Friction D. gravity 11. _____________ is a substance, which cannot be split or broken down into any simpler form by an ordinary chemical process. A. Mixture B. Element C. Compound D. Metals. 12. Alloys are best classified as A. elements B. compounds C. mixtures D. non-metals 13. A type of force which occurs when a body moves constantly over another body is the _______ A. static force B. dynamic force C. magnetic force D. frictional force. 14. Which of the following is NOT a characteristic of friction? A. The ratio of the frictional force and the normal reaction is constant. B. The frictional force is always equal to the force applied through weight. C. Static frictional force is independent of the surface area in contact. D. Friction supports motion. 15. Use of ball or roller bearing on a turning wheel of a machine A. can cause wear and tear of the wheel B. reduces friction between the wheel and the body parts of the machine C. decreases the efficiency of the machine. D. hinders the productivity of the machine. 16. Another way of reducing friction is by A. painting B. alloying C. oiling D. braising 17. A block of wood weighs 4N lies on a horizontal table. Calculate the frictional force between the table and the wood if the coefficient of the static friction is 0.5. A. 1.0N B. 0.2N C. 2.0N D. 0.4N 18. A body of mass 2kg was moved uniformly by a force of 15N, if acceleration due to gravity is 15m/s, determine the coefficient of dynamic friction. A. 0.75 B. 1.5 C. 0.5 D. 1.75 19. The symbol for Beryllium is A. B. B. Be C. Bl D. Bm 20. K is the symbol of A. Calcium B. Chromium C. Potassium D. Krypton

Answer 1

c. iron

Step-by-step explanation:

iron's atomic number is 26