Last Look - 1st Prep 2nd Term PDF

LAST LOOK (sc.revision 1ST PREP 2ND TERM) 1)What is meant by: 1-Atom:It is the smallest building and structure unit of any matter. 2- Isotopes:They are different forms of the same element ,have the same atomic no. but differ in mass no. 3-Positive ion:It is a metal atom that lost one or more electro...

LAST LOOK (sc.revision 1ST PREP 2ND TERM) 1)What is meant by: 1-Atom:It is the smallest building and structure unit of any matter. 2- Isotopes:They are different forms of the same element ,have the same atomic no. but differ in mass no. 3-Positive ion:It is a metal atom that lost one or more electrons in the chemical reaction. 4 -Negative ion :non-metal atom that has gained one or more electrons in the chemical reaction. 5 -Ionic bond:the electrostatic attraction between a positive ion (cation) and a negative ion (anion) 6- Covalent bond:It is the bond between two same non-metal elements or between two different non-metal elements by sharing electrons. 7—Valence electrons:They are the electrons found in the last energy levels of the element atom 8- boiling point : a temperature by which matter begins to change from liquid into gaseous state 9-melting point :It is a temperature by which matter begins to change from solid into liquid state 10- Magnetic materials :They are materials which are attracted to the magnet. 11- Non-magnetic materials:They are materials which are not attracted to the magnet. 12- Law of Attraction and Repulsion (similar) magnetic poles repel each other but (different) magnetic poles attract each other. 13- Magnetic field :It is the region of space around a magnet where the effect of its magnetic force appears. 14-Gravitational force :the force that (attracts) all objects downward towards the Earth’s center. 15- Contact forces: They are the forces that act on certain objects when they touch each other. 16- Field forces:They are the forces that act on objects over a certain distance without touching. 17-Orbital motion :It is the revolution of any object in space around another central body in a curved path due to the gravitational attraction force between them. 18- Object’s mass : It is the amount of matter an object contains. 19- Object’s weight:It is the gravitational force that Earth exerts on an object 20- Prokaryotes:They are unicellular organisms that don’t contain a true nucleus. 21- Eukaryotes: unicellular organisms or multicellular organisms that contain a true nucleus. 22- Cell: It is the basic building unit of structure and function in all living organisms. 23- Stem cells: They are undifferentiated cells that have the ability to be transformed and differentiated into all the differentiated cells to perform a specialized function. 24- Autotrophs organisms: organisms that can make their own food through photosynthesis. 25- Heterotrophs organisms :They are organisms that depend directly or indirectly on other producers to obtain their food. 26- Cellular respiration: It is a vital process of breaking down organic nutrients, especially glucose, in the presence of oxygen to release energy. 27- Microbes: They are microscopic living organisms that are found everywhere around us and they may be beneficial or harmful. 28- Root nodule bacteria: They are types of beneficial bacteria that live inside nodules on the roots of leguminous plants to provide the plant with nitrogen in a usable form. 29-The moon: It is a dark celestial body that orbits the Earth and it appears illuminated at the night sky 30- Umbra (shadow area) :It is a dark area that doesn’t receive any light rays as a result of the presence Earth in the path of sunlight. 31- Penumbra :It is a partially illuminated area that receives some light rays, which surround the shadow created by the presence of an opaque object in the path of light rays. 32- Transparent objects :They are objects that allow light to pass through them. 33- Opaque objects : They are objects that don’t allow light to pass through them. 34- Lunar eclipse : It is a natural phenomenon that occurs when Earth is located between the Sun and the moon, blocking sunlight partially or completely. 35- Total eclipse:It is a natural phenomenon that occurs when the moon is completely within the Earth’s shadow.moon turns red disc 36- Partial eclipse :It is a natural phenomenon that occurs when a part of the moon is in the Earth’s shadow and the other part is in the Earth’s penumbra 37-no eclipse: the whole moon is in the penumbra and turns into dim light 2) Mention the scientific reason: G.R 1- The nucleus of the atom is positively charged. Because the nucleus contains positively charged protons and neutrally charged neutrons. 2- The atom is electrically neutral. Because the number of positive protons inside its nucleus is equal to the number of negative electrons that revolve around the nucleus. 3- The mass of the atom is concentrated in its nucleus. Because electrons have negligible mass compared to the mass of protons and neutrons inside the nucleus. 4- Level (M) is saturated with electrons first before level (N). Because energy level (M) has energy lower than that of energy level (N). 5- All halogens are monovalent. -Because their Lewis structure contain 1 unpaired electron 6-The hydrogen molecule is considered an element molecule, while the sodium chloride molecule is a compound molecule. Because hydrogen molecule (H2) is composed of same atoms, while sodium chloride molecule (NaCl) is composed of different atoms. 7- Seawater is considered a homogeneous mixture. Because the components of seawater can’t be distinguished by the naked eye. 8- Wood floats on the surface of water, while iron sinks in it. – Because the density of wood is lower than that of water, so it floats on water. – Because the density of iron is higher than that of water, so it sinks in water. 9- Helium gas is used to fill balloons. Because helium gas is lighter than air and it is not flammable. 10- Nitrogen is used to fill car tires instead of air. Because nitrogen is not affected by temperature and doesn’t react with rubber. 11- Stainless steel alloy is used in the manufacture of cookware. Because stainless steel alloy resists rusting. 12- Aircraft structures are made of aluminum and titanium alloy. Because aluminum-titanium alloy is lighter than aluminum and retains strength at high temperatures. 13- Aerogel is used in making jackets for research scientists in Antarctica. Because Aerogel has excellent insulating properties, so it is used instead of using polar bear fur, helping to protect them from extinction. 14- Vitamin D is considered one of the important vitamins for the human body. Because Vitamin D regulates calcium and phosphorus levels in the blood to prevent osteoporosis 15-Nickel and cobalt are considered magnetic materials. Because nickel and cobalt are attracted to the magnet. 16- Aluminum and silver are non-magnetic materials. Because aluminum and silver are not attracted to the magnet. 17- A compass box is made of copper or plastic and not of iron. To prevent the attraction between the magnetic needle and iron which can affect its movement. 18- Iron filings are attracted in large amounts at each pole of the magnet. Bec.the attraction force of the magnet is the strongest at its poles, and it decreases at the middle 19- All objects fall downward to the Earth’s center. Due to the gravity force that pulls (attracts) all objects downward towards the Earth’s center. 18- The weight of an object on the Earth’s surface is greater than the weight of the same object on the Moon’s surface. Because the gravitational field of the moon is 1/6 the Earth’s gravitational field 19- Paramecia and euglena are considered unicellular organisms. Because their bodies consist of a single cell. 20- Bacteria differ from euglena, although they are both unicellular organisms. Because bacteria are prokaryotes, while euglena is from eukaryotes. 21- Green algae are considered producer organisms. Because green algae can make their own food through photosynthesis. 22- Rabbits are considered consumer organisms. Because rabbits depend directly on producers to obtain their food. 23-The surface of Mercury is full of craters. Because they are caused by meteorites impacts. 24- The atmosphere of Uranus appears blue-green in color. Because its atmosphere is composed of methane with hydrogen and helium 25 The moon appears bright even though it is an opaque body. Because the moon reflects the sunlight falling on it. 26- An observer on the Earth’s surface sees only one face of the moon. Because The time it takes for the moon to complete one orbit around the Earth is the same as the time it takes for the moon to complete one full rotation on its axis. 27- A shadow is formed when a book is placed in front of a lit electric lamp. Because the book is an opaque object that doesn’t allow light to pass through it. 28- No shadow is formed when a glass plate is placed in front of a lit electric lamp. Because glass is a transparent object that allows light to pass through it. 29- The total lunar eclipse phenomenon occurs. Because the entire moon is located within the shadow of the Earth (umbra). 30-The partial lunar eclipse phenomenon occurs. Because a part of moon is located within the shadow area of the Earth (umbra), while the other part is located in penumbra. 3) What happens in the following cases: 1 – The atomic radius when the atomic number of elements in the same group increases from top to bottom. ( -Atomic radius will increase) 2 – The atomic radius when the atomic number of elements in one period increases from left to right. ( -Atomic radius will decrease) 3- Increase the atomic radius in relation to the boiling and melting points of the alkali metals. -By increasing the atomic radius ,the melting and boiling points of the element will decrease 4- Increase in the atomic radius relative to the boiling and melting points of the halogen. -By increasing the atomic radius ,the melting and boiling points of the element will increase 5- To the acidified water if it is subjected to electrolysis? Water will decompose into its components, which are hydrogen gas and oxygen gas. 6- If you heat red mercury oxide compound? will decompose into its components, which are mercury (Hg) and oxygen gas (O 2). 7- If we dip a litmus paper in lemon juice? Its color will turn into red. 8- If we put a piece of wood in water? The wood piece will float on water. 9- A chlorine atom bonds with a sodium atom? An ionic compound called sodium chloride (NaCl) is formed by an ionic bond. 10- A chlorine atom bonds with a hydrogen atom? A covalent compound called hydrogen chloride (HCl) is formed by a single covalent bond. 11- A carbon atom bonds to four hydrogen atoms? A covalent organic compound called methane (CH4) is formed by four single covalent bonds 12- We rub the ebonite rod with a piece of silk and bring them close to each other? They will be attracted to each other because they have opposite charges 13-We touch a charged electroscope disc with your hand? We feel a slight electric shock because the electric charges are discharged. 14- We approach a positively charged glass rod close to a negatively charged electroscope? The divergence of the two gold leaves decreases. 15- A plant does not get nitrogen? The plant can’t form protein, which is very important for the growth of muscles and body building. 16- Farmers leave the roots of clover plants in the soil after harvesting the crop? The roots decompose by decomposition bacteria into nitrogenous compounds that are soluble in water, which increases the soil fertility. 17- Nodular bacteria on the roots of a bean plant are absent? The plant can’t obtain nitrogen in a usable form. 18- We add pre-prepared yogurt to the milk immediately after boiling? -Lactic acid bacteria will be killed. 19- The path of food in the digestive system is not a closed path. - Because food enters through the mouth and the waste products that not digested are eliminated through the anus 20- A person eats food and drinks water contaminated with Salmonella typhi bacteria? The person will be infected with typhoid disease. 21- A person eats food contaminated with Entamoeba histolytica bacteria? The person will be infected with dysentery disease. 22-Earth rotates around the Sun in a complete revolution? The cycle of seasons occurs. 23- Earth rotates around its axis in a complete rotation? -The cycle of day and night occurs and The apparent motion of the sun is the change in position from east to west 24-The Earth’s axis tilts toward the Sun one time and away from the Sun another time? Summer and winter seasons occur. 25 -The numbers of hours of night and day are equal? Spring and autumn seasons occur. 26- When a magnet is divided into several parts. each part becomes a new magnet with two poles 27-whenEarth aligns between the Sun and the moon. lunar eclipse occurred. 4) Complete the following sentences 1- Limestone rock is composed mainly of calcium carbonate molecules. 2- The atom is neutrally charged in its normal state, while the nucleus is positively charged. 3- Mass number is the summation of numbers of both protons and neutrons. 4- Mendeleev arranged the elements ascendingly according to their atomic masses, while Moseley arranged them according to their atomic numbers. 5- The elements of the (d)-block are known as transition elements 6- The element whose Lewis structure contains three unpaired electrons is trivalent. 7- The physical separation methods of mixtures include magnetic separation, filtration and evaporation and condensation. 8- Mixtures are classified into homogeneous mixtures and heterogeneous mixtures. 9- The components of heterogeneous mixtures can be distinguished by the the naked eye, and its components can be separated by filtration. 10- Table salt solution can be separated by evaporation and condensation 11-The chemical separation methods of compounds include heating and electrolysis. 12- A molecule of sulphuric acid H2SO4 contains 3 elements and 7 atoms. 13- The magnitude of static electric charges is measured by a device called coulomb meter. 14- Objects can be charged with static electric charges by rubbing or contact. 15- When a magnet is suspended freely, its south pole points to the geographical south pole of the Earth. 16-The Earth acts as a giant magnet, where the south pole of Earth's magnet represents the geographical north pole, while its north pole represents the geographical south pole of the earth. 17-Magnetic field lines starts from the north pole and end at the south pole. 18- Forces acting on objects are generally classified into contact and field forces. 19- Contact forces are those that act on objects upon contact, such as collision force and friction. 20-From the factors affecting the gravitational force between two objects is the mass of two objects and the distance between the centers of the two objects. 21-Tides are most active when the moon is shaped like either new moon or full moon. 22- Black holes are characterized by immense gravity force, even light can't escape from them. 23-Electrostatic force may be either attractive or repulsive between two charges, while gravitational forces are only attractive forces. 24- Light energy is converted into chemical energy stored in glucose material in the photosynthesis process. 25- The scientists have developed artificial photosynthesis to reduce global warming. 26- The artificial leaves are supplied with hydrogen gas and absorb carbon dioxide gas to produce environmentally friendly fuel. 27-- Water + Carbon dioxide + Light energy → Glucose + Oxygen. 28- The respiratory organ in the cockroach is tracheal tubes, while the respiratory organs in the adult frog are lungs and skin. 29- The lungs function in human like that of stomata in plants in excreting CO2 and excess water. 30- Glucose + Oxygen → Water + Carbon dioxide + Energy 31-Arteries transports oxygen and digested food from the heart to the rest of the body. 32- The transport system in the plant consists of xylem tissue and phloem tissue. 33- Xylem tissue transports water and mineral salts from the roots to the leaves. 34- Leaves of Mimosa plant are drooping and dangling when you touch it. 35- The plant needs nitrogen to form proteins used in the growth of their cells 36- Yogurt bacteria work to convert lactose into lactic acid. 37- Penicillin Notatum is used to treat bacterial diseases such as diphtheria and tonsillitis. 38- Yeast is used in making bread and production of ethyl alcohol. 39- Dysentery disease treated with antiprotozoal drugs, while Typhoid disease with antibiotics 40- Inner planets are rocky planets with solid surfaces, while outer planets are gaseous planets 41- Jupiter and Saturn are similar in that they have the same atmospheric components, and they do not have volcanoes in them. 42- Mars is known as the red planet, while Neptune is known as the blue planet. 43- Venus and Earth have many active volcanoes. 44- The two planets which consist of gases and ice are Uranus and Neptune 45-The apparent level of the Sun gradually rises between sunrise and noon. 46- The northern end of the Earth’s axis is tilted close to the sun in summer season and is tilted away from the Sun in the season of winter. 47-The phase in which three-quarters of the right part of the moon's side is illuminated is waxing gibbous phase. 22- When the side of the moon facing Earth is fully illuminated, it is called full moon (second quarter), while it is called new moon when it is completely dark. 5) Problem: An object has a mass equals 60 kg on the moon. Calculate: a) Its mass on Earth’s surface. = Mass on the moon = 60 kg. b) Its weight on Earth’s surface. =(w) = m x g = 60 x 10 = 600 N c) Its weight on moon's surface. = 600 x 𝟏/𝟔 = 100 N. (Knowing that Earth's gravitational field intensity is 10 N/kg) 8) Write the symbols (or the name) of the following elements: 1) Calcium. Ca 2) Aluminum. Al 3) Nitrogen. N 4) Oxygen. O 5) Phosphorus. P 6) Sulphur. S 7) Potassium. K 8) Barium. Ba 9) Boron. B 10) Sodium. Na 11) Chlorine. Cl 12) Argon. Ar 13) Helium. He 14) Magnesium. Mg 15) Neon. Ne 16) Lithium. Li 17) Hydrogen. H 18) Bromine. Br 19) Mercury. Hg 20) Gold. Au 21) Lead. Pb 22) Silver. Ag 23) Iron. Fe 24) Carbon. C 9-Locate the following elements in the modern periodic table (period, group and its block): 19K, 17Cl, 12Mg, 2He 19K Period: 4 Group: 1 (1A) Block: s-block. 17Cl Period: 3 Group: 17 (7A) Block: p-block. 12Mg Period: 3 Group: 2 (2A) Block: s-block. 2He Period: 1 Group: 18 (zero group) Block: p-block. 11-From the opposite figure: a) What is the name of the device shown in the figure? - Hoffmann voltameter. b) What is its use? - It is used in electrolysis of acidified water into its elements (hydrogen and oxygen gases). c) Write the items indicated by the numbers: -(1) hydrogen gas. (2) oxygen gas. With best wishes Mrs /Maha Abdel-Rahman 01289535453