chWho is he? * British chemist and physicist * Born 1887 * Scientific background * Eton * Trinity College Contribution and achievements * Discovered wavelength (energy) of an X-ray depended on the nuclear charge of an atom * Moseley observed and measured the X-ray spectra of various chemical elements obtained by diffraction in crystals. * The Moseley’s law. * Periodic Table. * Early X-ray crystallography * development of early X-ray spectrometry equipment
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model of the atom. (2.01) 10. What do we know about an atom if we know the atomic number? (2.02) 11. What does the atomic mass tell us about an atom? (2.02) 12. How many protons‚ neutrons and electrons are in an atom of Carbon? Explain how you determined them. (2.02) 13. How can an atom be electrically neutral? (2.02) 14. The atomic number of silver (Ag) is 47. A silver isotope has a mass of 108. How many electrons‚ neutrons and protons are in an atom of silver?
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Rutherford’s Gold Foil Experiment Rutherford started his scientific career with much success in local schools leading to a scholarship to Nelson College. After achieving more academic honors at Nelson College‚ Rutherford moved on to Cambridge University’s Cavendish laboratory. There he was lead by his mentor J.J. Thomson convinced him to study radiation. By 1889 Rutherford was ready to earn a living and sought a job. With Thomson’s recommendation McGill University in Montreal accepted
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evidence than a hypothesis. CHAPTER 2 Element- What matter is made up of. Cant be broken down by chemical reaction. Compound- Two or more different elements combined. Trace Elements- Required by an organism‚ but only in minute quantities. Atom- The smallest unit of
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organisms from plants to people. 1 of the 4 special features of carbon is that carbon atoms are able to bond with each other to form extended chains-sharing pairs of electrons with neighbouring carbon atoms which allow the formation of stable covalent carbon-carbon bonds. Carbon can also form branched chains and rings- these structures help to provide the skeletons of organic molecules. Number of carbon atoms in the chain is important because this influences the size and the shape of molecules.
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and the study of the atom A. Education and teaching career brought him in contact with amateur meteorologists B. Mentors and meteorology directed his interest toward air pressure and properties of gaseous elements C. Study of elements led to interest in components of elements and his atomic theory. D. This is the general path to his discoveries. However‚ no one knows specifically how he reached most of his conclusions about atoms. II. Work on the atom and its contribution
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distinct shapes are called ‘crystalline solids’. Crystalline solids are further divided into five groups: atomic‚ molecular‚ network‚ ionic‚ and metallic. The type of bonding in a substance depends on the type of atoms it contains and the forces of attraction that exist between the atoms. Some of these properties are hardness‚ solubility‚ electrical conductivity‚ and melting point. Ionic solids are those that have forces of attraction between oppositely charged ions. Ionic bonds allow the substance
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down into simpler substances by ordinary means. Four elements that compose our body. * Carbon: * Hydrogen: * Oxygen: * Nitrogen: Make up 96% of our bodies weight. Atoms Defined as the smallest non destructible parts of any element that will retain the characteristic of that element. Atoms have structures which means that structure means how a item is put together Contain nucleus‚ which contains protons and neutrons Protons: have an electrical charge and will weigh one
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Covalent Bonding In a covalent bond‚ a pair of electrons is shared between two atoms. Each of the positively charged nuclei is attracted to the same negatively charged pair of electrons. The diagram: A and B are held together by this shared attraction. Covalent bonds are often drawn as dots and crosses diagrams to show that the electrons have come from two different atoms. Molecules have a certain fixed number of atoms in them joined together by covalent bonds. Examples: Bonding in hydrogen
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formed from its elements under standard conditions. They are exothermic because new bonds are being made between the atoms of the elements sodium and chlorine. Na(s) + ½ Cl2 (g) NaCl(s) ∆Hf° (NaCl) = - 411 kJmol-1 ∆H1° standard enthalpy of atomization of chlorine. The energy required to change one mole of gaseous chlorine molecules into one mole of gaseous chlorine atoms. Endothermic because the
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