number of electrons as an argon atom? (a) F1- Na+ (b) Cl1- F1- (c) S2- Cl- (d) Mg2+ Ca2+ 3. Which of the following groups contains only covalent molecular substances. (a) KOH; NH3; CO2 ; NH4Cl (b) NH4Cl; Cl2; H2S; H2SO4 (c) HNO3; H2SO4; SO2; Na2O (d) H2O; H2S; NH3; CH4 4. The physical properties of solid metals can best be explained proposing that: (a) each metal atom is bonded in the crystal lattice
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indivisible atoms. An atom is an extremely small particle of matter that retains its identity during chemical reactions. 2. An element is a type of matter composed of only one kind of atom, each atom of a given kind having the same properties. Mass is one such property. Thus, the atoms of a given element have a characteristic mass. 3. A compound is a type of matter composed of atoms of two or more elements chemically combined in fixed proportions. The relative numbers of any two kinds of atoms in a compound
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Structure and Properties Section 2.8 - Atoms and the Mole: How Many Particles? Section 1.9 – Atomic Mass: The Average of an Element’s Atoms The purpose of this activity is to better understand the concepts of relative atomic mass, counting by weighing and the mole. Per cent composition and average atomic mass are included. Part I. Relative Atomic Masses and the Mole – Early Method When John Dalton proposed his atomic theory, he stated that the atoms of each element had a characteristic mass. He carried
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1. How many elements are essential? a. Approximately 20-25% of the 92 natural elements are considered essential, this is about 17-25 elements. 2. Which elements make up 96% of matter on earth? a. The four elements that make up 96% of all matter are the elements oxygen (O), hydrogen (H), nitrogen (N), and carbon (C). 3. What subatomic particles are found in the atomic nucleus? What are their charges? a. There are three subatomic particles found in an atom’s nucleus and they are electrons, protons
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PHYSICAL CHEMISTRY CHAPTER 1 Principle of Chemistry Relative Atomic Masses of atoms & molecules Mass number & atomic number Atomic structure (neutrons, protons & electrons) Mole concept & conversion Avogadro’s concept Empirical & molecular formulae Isotopes FHSC1114 Physical Chemistry 1 Centre for Foundation Studies, UTAR Objectives To define relative atomic masses of atoms & molecules To define & determine mass no. & atomic no. To determine no. of neutrons, protons
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1. Atom The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons Atoms are made up of three basic particles: Protons-carries a positive charge Neutrons-carry no charge Electrons-carry a negative charge and encircles the nucleus. (http://education.jlab.org/atomtour/listofparticles.html) 2. Element A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the
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for CH3OH is 32. It is an integer, and is sum of integer masses of elements present in sample compound. Isotopic mass is the exact mass of an isotope of an element, and it is 12 for C12, it is only integer mass. For all other isotopic atoms mass is determined with reference to C12, 1/12 of carbon is µ, is equal to 1.66055x10-27 kg, is taken as standard mass since 1961. Isotopic mass is the mass of that particular atom of an element with reference to C12, 12.000000, For C13; it is 13.000355 for hydrogen
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There are two different elements in a water molecule. 2. Atoms heavier than hydrogen were made by nuclear fusion. 3. If we doubled the magnifying power of the most powerful optical microscope in the world, we would still not be able to see an atom. 4. Chemical compounds are made up of about 100 distinct elements. Atoms are the smallest subdivision of matter that still retains chemical properties of a substance. A quark is the smallest particle that exists. Electrons form atoms that in turn determine
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Atoms, Molecules and Ions. AN ATOM is the smallest particle of an element. They cannot be split into smaller particles in chemical reactions. Iron is made of iron atoms (Fe). Sulphur is made of sulphur atoms (S) A MOLECULE is a small group of atoms joined together. The atoms may be the same (e.g. O2) or different (e.g. H2O). The chemical formula shows the number and type of atoms present. Non-metal compounds are made of molecules: Carbon dioxide contains CO2 molecules Methane (natural gas)
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SCI Ch.1 – Ch.10 Outline Ch. 1 The scientific law describes an important relationship that is observed in nature to occur consistently time after time. A model is a description of a theory or idea that accounts for all known properties. The steps in the scientific method includes 1. Observation 2. Question 3. Background research 4. Hypothesis 5. Methods 6. Equipment 7. Experiment; collect data 8. Results; analyze results 9. Conclusions 10. New hypothesis. A hypothesis should start with
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