COE CHEMONE Reviewer for CHEMONE Finals Rules for Counting Significant Figures 1. Nonzero integers. Nonzero integers always count as significant figures. 2. Zeros. There are three classes of zeros: a. Leading zeros are zeros that precede all the nonzero digits. These do not count as significant figures. In the number 0.0025‚ the three zeros simply indicate the position of the decimal point. This number has only two significant figures. Note that the number 1.00 _ 102 above is written in exponential
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non-polar covalent bonds. Example: H2 ‚ Cl2 ‚ I 2 Polar molecular solids → The molecules ion these types of solids are held together by strong dipole-dipole interactions. Example: Solid SO 2 ‚ solid NH3 Hydrogen-bonded molecular solids → The molecules of such solids contain polar covalent bonds between H and f‚ O or N atoms. Example: Ice (H2 O) Ionic solids Ions are the constituent particles; e.g.‚ NaCl‚ KNO 3 Metallic solids Each metal atom is surrounded by electrons; e.g.‚ Fe‚ Cu Covalent or network
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1. The diagram below shows the electronic structure of boron. (a) The electrons are represented by arrows. What property of the electrons do these ‘up’ and ‘down’ arrows represent? ..................................................................................................................................... (1) (b) Suggest why electrons which occupy the 2p sub-levels have a higher energy than electrons in the 2s sub-level. .....................................................
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l the different types of compounds that we have learnt this unit. Your audience will be students beginning their grade ten who have minimal knowledge on writing chemical formulas. They are able to: • Read the periodic table and identify metals‚ metalloids‚ and non‐metals • Identify polyatomic‚ but don’t have them memorized • Read the oxidation states (charges) on the periodic table However‚ you should assume that they have no knowledge on ionic and covalent bonds‚ criss‐cross rule‚
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[pic] Note: It’s important to realise that this is an average picture. The electrons are actually in a molecular orbital‚ and are moving around all the time within that orbital. [pic] This sort of bond could be thought of as being a "pure" covalent bond - where the electrons are shared evenly between the two atoms. What happens if B is slightly more electronegative than A? B will attract the electron pair rather more than A does. [pic] That means that the B end of the bond has more than
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substances: an element and a compound. Element: A substance that cannot be broken down by chemical means. An element is a pure substance because it is made up of one type of atom it also cannot be broken down further into another substance. (This deems it pure) Compound: A substance that is made up of 2 or more elements‚ it is still considered a pure substance because while the elements bond so do the atoms. Therefore there is only one type of atom in the compound. Impure substance- Mixture:
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Lesson 1.1 - Study Materials Slide 1 Lesson 1.1 : Scientific Method 1. Steps of the Scientific Method The scientific method (performing a study in organized steps) consists of: For example‚ applying the scientific method ultimately led to the enunciation of the Law of Conservation of Mass and Matter. Slide 2 1. Steps of the Scientific Method Step 1: Performing Experiments An experiment is a set of steps (procedures) that are performed under controlled conditions to propose or test
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other members of the group After studying this unit‚ you will be able to • describe the general characteristics of the alkali metals and their compounds; • explain the general characteristics of the alkaline earth metals and their compounds; • describe the manufacture‚ properties and uses of industrially important sodium and calcium compounds including Portland cement; the biological significance of sodium‚ potassium‚ magnesium and calcium. • appreciate The s-block elements of the
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volume of a cylinder = πr2h Form A 1) Convert 127° F to Kelvin? A) 95.0 K B) 475 K C) 53.8 K D) 400 K E) 326 K 2) In what ratio do the elements represented by the electron configurations 1s22s22p63s1 and 1s22s22p3 combine to form a compound? A) 3:1 respectively B) 2:3 respectively C) 3:2 respectively D) 1:4 respectively E) 1:3 respectively 3) Which of the following elements is the most electronegative? A) P B) Cl C) As D) S E) Te 4) A chemical property of a substance is
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The Bohr Theory explains that an emission spectral line is due to an electron losing energy and changing orbitals. 2. 4s orbitals have higher energy than 3d orbitals. 3. An atom with an even number of electrons is always diamagnetic. 4. Covalent bonds are formed by atoms sharing electrons. Multiple Choice 5. Choose the INCORRECT statement about NH2-: a) There is one lone pair on N. b) There are two σ bonds. c) There are no π bonds. d) The molecule is bent. e) N is sp3 hybridized
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