CHAPTER 10 - Radioactivity and Nuclear Processes Composition of atomic nucleus - neutrons and protons Nuclides are nucleus of different isotopes, which is represented by the symbol [pic]X - X being symbol of the element. A is the mass number, which is the sum of number of protons & neutrons; Z is the atomic number, the number of protons, which also represents the nuclear charge. Number of neutrons = (A – Z). For example, the symbol of carbon-14 nuclide is [pic]C, which means a carbon-14 nuclide has 6 protons and 8 neutrons. The nuclide symbol of lead-206 is [pic]Pb.
Chemistry Design Lab Kim Li Feb 20th,11 Investigating the effect of different concentration of nitric acid on the its drop volume DESIGN Introduction: Intermolecular forces are forces that hold molecules together. They play important roles in determining the properties of a substance, properties such as boiling point, volatility, viscosity, miscibility, and electrical conductivity.  Examples of intermolecular forces include Van der Waals forces, dipole-dipole forces, and hydrogen bonding. Van der Waals forces are temporary dipole all species can form due to uneven distribution of electrons. Dipole-dipole forces are permanent dipoles due to different electronegativity.
Main – group metals usually for one cation (positive ion). In a binary ionic compound the metal (cation) is named first. Then the nonmetal (anion) is named, and the suffix -ide is added. To create the formula, you switch the charges, and that tells you how many of each element you will need. For example: Cation Anion Formula Name of Compound Ba2+ I- Ba2+ I- Barium Ion Iodide Ion BaI2 Barium Iodide Type 2: Binary Ionic Type 2 Binary Ionic compounds consist of a metal and a nonmetal.
The first shell can hold up to 2 electrons, second shell can hold up to 8 electrons, third shell can hold up to 18 electrons and the fourth shell can hold up to 32 electrons. The electron configuration is determined by the number of electrons in the outer valance shell and it is used to describe the orbitals which are occupied by the electrons of the atom. The Bohr model of the quantum atom is considered as the cornerstone of quantum mechanics even though it is fundamentally incorrect for all atoms other than hydrogen because Bohr proposed the idea of quantisation for hydrogen’s electronic structure also he was able to explain the emission spectra of hydrogen as thoroughly as other one-electron system. Bohr used spectral evidence to test his atomic theory and he was able to predict that the energy emitted and absorbed by an electron when it changes orbitals would be equivalent to a certain wavelength of electromagnetic radiation and it is possible for it to be measured. He found evidence of his theory of atomic structure which he studied about the spectra and which he chose a specific one which was the hydrogen
They are composed of an equal number of cations and anions so that the product is electrically neutral. Sodium chloride is an ionic compound with the formula NaCl, representing equal proportions of sodium and chloride. When salt comes into contact with ice, it tends to break apart into individual ions which then interact with the frozen disrupt hydrogen bonds that have formed between ice molecules. This lowers the melting temperature of ice. I hypothesise that the higher the
The consequence is that only special values of radius and energy are allowed. The mathematical appendix explains how to calculate these values. According to classical electrodynamics, a charge, which is subject to centripetal acceleration on a circular orbit, should continuously radiate electromagnetic waves. Thus, because of the loss of energy, the electron should spiral into the nucleus very soon. By contrast, an electron in Bohr's model emits no energy, as long as its energy has one of the above-mentioned values.
(2) hydrogen ion contains 1 electron and 1 proton, H+ ion forms when H ion lost an electron, and therefore it’s is the same thing as a proton 6. What is the chemical formula for a hydronium ion? (1) H3O+ 7. Show the relationship between a proton and a hydronium ion. Explain why one is essentially the same as the other.
Gallium, indium, aluminium, boron. Indium, gallium, aluminium, boron. JSC 2006, Physical Science [Turn over 2 5 The combination of protons, neutrons and electrons for a neutral atom of magnesium, 24 Mg, is: protons electrons A 10 14 11 B 11 13 12 C 12 12 12 D 6 neutrons 12 12 10 Which structure represents an atom of the noble gas in the first period. e e e pn np np pn n np p e e e e e e A 7 e e e pnn pnn npp e B C e e e D A mixture containing a soluble salt, sand and iron filings, can be separated into its components using techniques: R: use of
The charge on a mole of electrons for some time and is the constant called the Faraday. The estimate of the value of a faraday is 96,485.3383 coulombs per mole of electrons. The estimate of the charge on an election base is 1.60217653 x 10^-19 coulombs per electron. Divided the charge of a mole of an election obtains the value of 6.02214154 x 10^23 particles per mole. According to Bender oxygen and hydrogen are elements other than carbon used to define mole.
Si, P, S and Cl are increasingly electronegative. They cannot form oxide ions from oxygen at all, so they behave as acids. The trend is from strongly basic oxides on the left-hand side to strongly acidic ones on the right, via an amphoteric oxide (aluminium oxide) in the middle. In addition, when going across the period 3 the acid-base nature of the oxides change from base to amphoteric and finally to become acid. This is because the less electronegative sodium has a weak Na-O bond and the oxygen is more easily given up to reacts with H+.