The new answers to the eighth grade science are 1 atomic elements 1 atoms, molecules and ions 1 the first class 1.b2.c3.a4.a5.d6.c 2, 1. The minimum amount of 1 mL-2 mL only needs to cover the bottom of the test tube. 2. The liquid is flat or inverted to corrode the rubber head. Rinse the inside of the test tube (or contact the tube wall) with clean water. 3. The measuring cylinder is stable at the lowest level. 4. Tilt to the palm of your hand to prevent the liquid medicine left in the bottle mouth from flowing down and corroding the label. 5. Red ink spreads around, and the whole glass of water turns red, and there are particles invisible to the naked eye, which are constantly moving. (2) Phenolphthalein on the filter paper turns red when it meets alkali. (3) It shows that there are invisible particles in matter, and these particles are constantly moving. Category II: I, 1.b2.d3.b4.a5.c6.b7.c II, 1. √2.√3.X 4。 X 5。 √6.√ 3, 1. Nuclear electrons, nuclear electrons, non-electric nuclei II. Nuclear power (2) There are organisms on the wall of the beaker, and the released invisible particles contact with the solution in beaker A, making it turn red; (3) The concentrated ammonia in beaker B releases an invisible particle, which slowly dissolves into the solution of beaker A, making solution A turn red. (2) Description: ① Ammonia can make phenolphthalein test solution turn red; ② Some invisible particles escaped from the concentrated ammonia water in beaker B, and some particles entered the solution in beaker A, which changed the composition of the solution and turned the color red. Design experiment: ① Add 20 mL distilled water into a clean beaker C and drop 2-3 drops of phenolphthalein test solution. Stand still and observe the phenomenon; Cover it separately in a big beaker and observe the phenomenon. ② Take two beakers instead of A and B, the solution in one bottle is the same as that in A, and the other bottle only uses distilled water instead of concentrated ammonia water. If the picture is put away, observe the phenomenon. ③ Take a small amount of concentrated ammonia water from beaker B and inject it into the test tube, and then add phenolphthalein test solution dropwise to observe the phenomenon. ④ Drop a small amount of concentrated ammonia in beaker B into beaker C and observe the phenomenon. 2.( 1) The nucleus is very small, and the space inside the atom is very large. (2) The nucleus is positively charged. When a particle passes near the gold core, it is repelled and changes its direction of motion. (3) The mass of gold core is much greater than that of particle A, and particle A will bounce back when it hits the gold core. Lesson 3: 1. 1.C2。 1. Positive and negative equals opposite negative and positive. 2. ionic atom molecule ionic atom 3. Atomic cation anion 4. Atoms gain and lose electrons. 2. lose electrons. 3. lose electrons. 4. Lesson 41.c2.d3.b4.d5.d6.a7.d8.B9.c10.a II. 1.x2.x3.√ 4。 √5. X6√7. XIII .. But there are real gaps between molecules; 2) Molecular atoms, ions, iron atoms, chloride ions and sodium ions; 3) Physical space among water molecules, water molecules, hydrogen atoms and oxygen atoms; 4) carbon-12 atom,1125. (1) The rubber-tipped dropper sucks and drops a small amount of test solution; 2) It is convenient to observe the color change of phenolphthalein test solution. Near the test tube mouth, it turns red first, then red in turn, and keeps moving. (4) Two test solutions are dripped backwards or both are dripped on cotton. Concentrated ammonia 4, 1. Stopping the cork can prevent alcohol and gasoline vapor molecules from spreading into the air due to continuous movement, resulting in volatilization and waste of alcohol and gasoline. 2. There are relatively large gaps between gas molecules. When gas is compressed, the distance between gas molecules becomes smaller, so its volume becomes smaller accordingly. V.56 Six. (1) Pour a small amount of water into an evaporating dish and heat it with an alcohol lamp. The evaporation of water shows that molecules are in constant motion. Or you can smell alcohol by opening the cork of the reagent containing alcohol. (2) The total volume of 50 ml of alcohol and 50 ml of water mixed with a measuring cylinder is less than 100 ml, which proves that there is a certain interval between molecules. 1.2 element 1 the first kind, 1. A2.B3.C4.C5.A6.C7.D II， 1。 Oxygen (o) nitrogen (n) water (H2O) aluminum (A 1 carbon atom oxygen 1 carbon atom 2 oxygen atom 3. Proton number element 4. Oxygen element oxygen atom proton number (or nuclear charge number) oxygen element 5. Composition composition 3. 1. Particles with the same number of protons are not necessarily the same element, because "particles" can be both molecules and atoms or ions. For example, each CH4 molecule and Ne atom contains 10. 2. Potassium chlorate itself contains no oxygen. Using potassium chlorate to make oxygen is the product of the chemical change of potassium chlorate, which only shows that there is oxygen in potassium chlorate, but it cannot be said that there is oxygen in potassium chlorate. 3. Metals are not made of molecules, but directly made of atoms; Before and after all chemical reactions, the types of elements will not change; Gold is directly composed of gold atoms, and the composition element is only gold; Aluminum is directly composed of aluminum atoms, and the composition element is only aluminum. Class 2: Me, 1. C2.D3.B4.C5.D2， 1。 C, Ca, Na, Al, Mg, I, Hg and Fe. ( 1)Fe(2)C(3)H(4)Au(5)Zn(6)N(。 Page 3. One atom of the element: hydrogen element 1 hydrogen atom 2H. The third category, 1 class, 1. D2 a3 . D4 . C5 . B6 . D2， 1.2n 3 Fe 2 he 2h2o 2.2 H2O 3·2h2o 3。 (1) 2 chlorine atom. (2