Unit 1 Test Study Guide PDF

Why is NaCl not toxic? Periodic Table and polyatomic ions will be provided. Elements, compounds, (homogeneous/heterogeneous) mixtures and pure substances. What are they and how can you recognize them? What are properties of each? Can you classify...

Why is NaCl not toxic? Periodic Table and polyatomic ions will be provided. Elements, compounds, (homogeneous/heterogeneous) mixtures and pure substances. What are they and how can you recognize them? What are properties of each? Can you classify items as each of the above? Element- made only of one kind of atom-can be broken down chemically Compound-2 or more elements chemically combined- only broken down with chemical reactions. Mixture- 2 or more elements or compounds physically combined- can be separated by physical means -Homogeneous- composition is consistent throughout sample -heterogeneous-composition is not uniform(same) throughout Pure substances-Can not be separated by physical means. - Have a fixed composition- either compounds or elements What is a molecule and can you name the diatomic 7 elements? Molecule- formed when two or more atoms join together chemically. Diatomic molecules- come in 2s like Hydrogen, Oxygen, Nitrogen, Fluorine, chlorine, Bromine, Iodine ㄱ Shape in the periodic table. What happens when sodium hits water? o Sodium dissolved water Physical and chemical changes. What are they and what are some examples? Physical and chemical properties. What are they and what are some examples? o Chemical-burns, reacts to a new substances. o Physical- Changes in size, shape, mass, melts,boils, and dissolves o Chemical- Not easily reversed - New products formed - Reactants used up - Often heat/light/sound/ fizzing occurs - Electricity maybe produced - A precipitate(용액에서 고체가 분리되는 일이다. 즉 용액이 온도 및 물리적 영향을 받아 녹았던 용질이 고체의 결정으로 만들어지는 일이다) o Physical change-Easly reversible -No new products - often just a stage change -ex- ice melting Endothermic and exothermic reactions. What happens in each? Can you identify them by looking at a temperature change of a substance on a graph? What does an endothermic reaction feel like? What does an exothermic reaction feel like? o Endothermic reaction- Took heat in from the water ( temp went down) o Exothermic reaction- Gave heat off to the water ( temperature went up) Reactivity pattern of metals. Can you explain the reactivity of group 1 elements in water? What about the reactivity of group 2 elements in water? o Reactivity of the metals with water is related to the periodic table. As you go down a group/column, there are lose patterns in the heat released when the salts(chloride) dissolve in water that can be tied to the reactivity of the metals.  How can we use physical and chemical properties to organize elements? o Chemical property – Flammability - React with acid - Support combustion - React with water - React with air o Physical properties-atomic mass - State of matter - Shape - Temperature - Texture - Luster( 광택) - Density (밀도) - Taste - Melting point - Hardness - Odor - Color - Solubility ( dissolve) The Periodic Table. Do you know where to find: metals, non metals, metalloids, alkali metals, halogens, noble gases? o Metal- the positive charge Side and the middle part o Nonmetal- negative charges atoms o Metalloid- An element whose properties are intermediate between those of metals and solid nonmetals or semiconductors. Do you know these words…period, group, family…and how they relate to the periodic table? o Period- Along with horizontal rows o Groups(also called family)- along with the vertical columns What are some properties of metals and nonmetals? o Metal- any of the elements with a positive electrical charge, typically with a shinny surface and a good conductor of heat. 805 of elements on the periodic table. o Non metal- Can be gases, liquids or solids. Non- metals are dull in colors, not shiny like metals. Non-metals don’t conduct electricity well- they are insulators Can you identify groups 1-8? (8 is sometimes called group 0) What about groups 1-18? How do they relate to each other? o Group 1- Alkali metals o Group 2- Alkaline earth metals o Group 3-12- Transition metals o Group 13- Boron group o Group 14- carbon group o Group 15- Nitrogen group o Group 16- Oxygen group, chalcogen o Group 17- Halogens o Group 18- Noble gases  What happens when like charges come together? What happens when opposite charges come together? How do things become charged? What happens to the force when charged items get closer together/farther apart? o When like charges come together, they repel o When opposite charges come together, they attract o The closer they are, the stronger attraction/repulsion. o Increase in the distances between the objects, decreases the likelihood that things will attract What are the parts of the atom? Where is each part located? What kind of charge do each of those parts have? What was Rutherford’s experiment and what did it tell us? o Alpha particle that we shot at a thin piece of gold leaf. o Most of the particle went through but only 1/10000 bounced pack which was a tiny positive nucleus. o Result- There is a tiny and positive nucleus in the atom - Atom is mostly empty space - Nucleus is positive - Electrons are negative How can you find the atomic number of an element? What does this mean for the number of protons? What does it mean for the number of electrons of a neutral atom? o Atomic number is the number of protons and the one on the top of the element symbol in the periodic table. o Atomic number= number of electrons in neutral form What is an isotope? What do all isotopes of the same element have in common? o Atoms of the same element with different mass number o All of the isotopes have mass number on the top and atomic number on the bottom What does carbon-12 mean? How many protons are there? How many electrons are there? What is the mass number? How many neutrons are there? o Carbon-12 means a hyphen notation. 12- mass number. Because atomic number is 6, then the protons and electrons are 6 too. Neutron is always mass number-Atomic nubmer 59 Consider 28 Ni. How many protons are there? How many electrons are there? What is the mass number? How many neutrons are there? - 59 on the top is mass number - 28 is atomic number , protons, electrons - 59-28= 31 = neutrons What is an ion? How do positive ions form? What is another name for a positive ion? How do negative ions form? What is another name for a negative ion? Can you find the charge on an ion if you know the protons and electrons? Can you find protons and electrons if given the symbol? o Ion – occur when atom or molecule that has gained or lost electrons- result in a net electrical charge.  o Positive ion forms when an atom loses one or more electrons. Positive= cation o Negative ion- forms when an atom gains one or more electrons. Negative= anion What is ionization energy? Can you look at a chart of ionization energies and tell what charge something is likely to have when it becomes an ion? Can you look at a chart of ionization energies and tell how many outer shell electrons something will have? What are these outer electrons called? How many outer electrons does each group (1-8) have? o Ionization energy- Energy a neutral atom needs to remove an electron from. o Outer electron is called valence electron which is the group number. o So group 1=1 outer electron 2=2 3=3 What is the trend in ionization energy as you go across a row on the periodic table? Why? What is the trend in ionization energy as you go down a group on the periodic table? Why? What does the distance from the nucleus have to do with ionization energy? o Low ionization on the left size- because only need few energy to remove 1-2 valence electrons o High ionization for the right side o More distance between the ring- more ionization energy What is the trend in atomic size as you go across a row? Why? What is the trend in atomic size as you go down a group? Why? What does the pull on the electrons by the nucleus have to do with the size? o Atomic radius decrease from left to right o The bigger the atom is, the easier it is to remove an electron and be more reactive What is the trend in reactivity of group 1 and group 2? What does ease of removing an outer electron have to do with this? o Have only few first ionization energy needed which is easy for removing an outer electron. Do the halogens follow the same reactivity trend of groups 1 and 2? If not, what is the trend? o No the halogen group’s reactivity gets fewer when we go down into the group Why does sodium react differently than lithium? o The energy to remove the first electron in sodium is lower than the energy to remove the first electron in lithium. o As we go down group 1, the elements become more reactive and it becomes easier to remove the firs electrons. o The energy needed to removed the FIRST electron is called the 1st ionization energy. What is electronegativity? What is the trend as you go across a row? Why? What is the trend as you go down a group? Why? o Electronegativity is the tendency of an atom to attract the electrons in a bond towards it while ionization. o The more you go down, less electronegativity o Left to right- low electronegativity to high What is spectroscopy and how can we use it to identify different elements in a substance? What might be a limitation in using flame tests in identifying elements? o Spectroscopy- the science of using spectral lines to figure out what something is made of. o It can tell what elements they are looking at just by reading the lines o There is a lot of colors that are same so It is hard to distinguish the element in the flame test. Can you draw a Bohr model? How many electrons can fit on each shell? o yes What are ionic bonds and how are they formed? o Contains 2 kinds of elements  o Type of chemical bond that occurs between atoms when there is a transfer of electrons from one atom to another. It led to formation of ions which charged particles that result from the gain or loos of the electrons. o Ionic compounds. Can you find the charge for an ion by looking at the periodic table (except in the case of transition metals)? How does this relate to the group number? Do noble gases form ions? Can you put 2 ions together to form a compound? What is the criss-cross method? Yes What happens to the name of a negative ion? Can you name a binary ionic compound from a formula? It changes into ide. Yes How can we show the charge of a transition metal when naming an ionic compound? Why do we need to do this? o To show the charge of a transition metal in an ionic compound, use Roman numerals after the metal’s name, indicating its oxidation state. Can you name a compound containing a polyatomic ion? Can you write the formula of something containing a polyatomic ion? When do we use parenthesis when writing a formula? o Indicating polyatomic ions that occur more than once in a compound o Showing multiple identical groups of atoms or ions o Representing complex ions in coordination compounds. o Avoiding ambiguity in the interpretation of the formulas What is a double replacement reaction? What will one of the products of a double replacement always be reaction be (there are 3)? What is a precipitate and how can you identify it? o Double replacement reaction involves the exchange of ions between two compounds resulting in the formation of two new compounds. o One of the product is often a precipitate which is an insoluble solid formed from the reaction. What does it mean for something to be “aqueous” (aq)? What does this have to do with precipitates? What happens when a soluble ionic compound is dissolved in water ? o As means substance is dissolving in water.