希臘 - 中正大學化生系
... chemical properties; as is apparent among other series in that of Li, Be, B, C, N, O, and F. 4. The magnitude of the atomic weight determines the character of the element, just as the magnitude of the molecule determines the character of a compound body. 5. We must expect the discovery of many yet u ...
... chemical properties; as is apparent among other series in that of Li, Be, B, C, N, O, and F. 4. The magnitude of the atomic weight determines the character of the element, just as the magnitude of the molecule determines the character of a compound body. 5. We must expect the discovery of many yet u ...
Chapter 2: Matter
... Ex. Hydrogen, oxygen, and nitrogen occur naturally as colorless gases but when combined they form Nylon which is a flexible solid. ...
... Ex. Hydrogen, oxygen, and nitrogen occur naturally as colorless gases but when combined they form Nylon which is a flexible solid. ...
V. Chemical reactions
... b. Which elements have two valence electrons? Column 2 c. Which elements have three valence electrons? Column 13 d. Which elements have four valence electrons? Column 14 e. Which elements have five valence electrons? Column 15 f. Which elements have six valence electrons? Column 16 g. Which elements ...
... b. Which elements have two valence electrons? Column 2 c. Which elements have three valence electrons? Column 13 d. Which elements have four valence electrons? Column 14 e. Which elements have five valence electrons? Column 15 f. Which elements have six valence electrons? Column 16 g. Which elements ...
chapter-2 - HCC Learning Web
... Hydrogen Bonds • A hydrogen bond forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom • In living cells, the electronegative partners are usually oxygen or nitrogen atoms ...
... Hydrogen Bonds • A hydrogen bond forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom • In living cells, the electronegative partners are usually oxygen or nitrogen atoms ...
Slide 1 - Effingham County Schools
... • Aristotle was wrong. However, his theory persisted for 2000 years. ...
... • Aristotle was wrong. However, his theory persisted for 2000 years. ...
The Atom Power point - Effingham County Schools
... • Aristotle was wrong. However, his theory persisted for 2000 years. ...
... • Aristotle was wrong. However, his theory persisted for 2000 years. ...
ch14
... Compounds of 3A elements have more covalent character than similar 2A compounds. Aluminum has the physical properties of a metal, but its halides exist as covalent dimers. ...
... Compounds of 3A elements have more covalent character than similar 2A compounds. Aluminum has the physical properties of a metal, but its halides exist as covalent dimers. ...
Document
... Are attractive forces in which hydrogen that is covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another ...
... Are attractive forces in which hydrogen that is covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another ...
Exam Review
... J) Draw the electron dot diagram (Lewis Dot Structure) and then tell if it would give up or take on electrons to get a full shell. Also tell what charge it would have (positive or negative and how much ex: +2) ...
... J) Draw the electron dot diagram (Lewis Dot Structure) and then tell if it would give up or take on electrons to get a full shell. Also tell what charge it would have (positive or negative and how much ex: +2) ...
Unit 4: Chemical Bonding Notes Chemical Bond—a mutual
... Other atoms can fill their outermost s and p sublevels by sharing electrons through covalent bonding. Such bond formation follows the octet rule: Chemical compounds tend to form so that each atom, by ...
... Other atoms can fill their outermost s and p sublevels by sharing electrons through covalent bonding. Such bond formation follows the octet rule: Chemical compounds tend to form so that each atom, by ...
Review Outline for Atomic Structure Test
... J) Draw the electron dot diagram (Lewis Dot Structure) and then tell if it would give up or take on electrons to get a full shell. Also tell what charge it would have (positive or negative and how much ex: +2) ...
... J) Draw the electron dot diagram (Lewis Dot Structure) and then tell if it would give up or take on electrons to get a full shell. Also tell what charge it would have (positive or negative and how much ex: +2) ...
apbio ch 2 study guide
... Hydrogen bonds form when a hydrogen atom that is already covalently bonded to one electronegative atom is attracted to another electronegative atom. o In cells, the electronegative partners are typically nitrogen or oxygen. o Hydrogen bonds form because a polar covalent bond leaves the hydrogen atom ...
... Hydrogen bonds form when a hydrogen atom that is already covalently bonded to one electronegative atom is attracted to another electronegative atom. o In cells, the electronegative partners are typically nitrogen or oxygen. o Hydrogen bonds form because a polar covalent bond leaves the hydrogen atom ...
- Catalyst
... 1. Every atom contains small, dense nucleus. 2. All of the positive charge and most of the mass are concentrated in the nucleus. 3. The nucleus is surrounded by a large volume of nearly empty space that makes up the rest of the atom. 4. The rest of the atom is thinly populated by electrons, the tota ...
... 1. Every atom contains small, dense nucleus. 2. All of the positive charge and most of the mass are concentrated in the nucleus. 3. The nucleus is surrounded by a large volume of nearly empty space that makes up the rest of the atom. 4. The rest of the atom is thinly populated by electrons, the tota ...
Chemistry Final - Practice Test I
... (a) has protons, neutrons, and electrons (b) has protons and neutrons (c) retains the chemical identity of that element (d) can form an ion The atomic number (# of protons) and mass of chlorine are? (a) 17, 35 (b) 33, 75 (c) 16, 32 (d) 29, 64 The neutrons of an atom are found: (a) in the nucleus (b) ...
... (a) has protons, neutrons, and electrons (b) has protons and neutrons (c) retains the chemical identity of that element (d) can form an ion The atomic number (# of protons) and mass of chlorine are? (a) 17, 35 (b) 33, 75 (c) 16, 32 (d) 29, 64 The neutrons of an atom are found: (a) in the nucleus (b) ...
Chemistry Review ATOMS
... • The mass of atoms and molecules is neither created nor destroyed in chemical reactions. – The # of atoms for each element in the reactants must equal the # of atoms for each element in the products in a chemical reaction. – Chemical Equations must be balanced. ...
... • The mass of atoms and molecules is neither created nor destroyed in chemical reactions. – The # of atoms for each element in the reactants must equal the # of atoms for each element in the products in a chemical reaction. – Chemical Equations must be balanced. ...
Atomic Systems and Bonding
... When the valence electron in any atom gains sufficient energy from some outside force, it can break away from the parent atom and become what is called a free electron Atoms with few electrons in their valence shell tend to have more free electrons since these valence electrons are more loosely boun ...
... When the valence electron in any atom gains sufficient energy from some outside force, it can break away from the parent atom and become what is called a free electron Atoms with few electrons in their valence shell tend to have more free electrons since these valence electrons are more loosely boun ...
PVS103 - unit 6 notes
... We have already seen how electronegativity increases on moving across the periodic table. Can you remember why? As a result electronegativity is a periodic property, so for example, the halogens (Group 7a elements) are all highly electronegative. ...
... We have already seen how electronegativity increases on moving across the periodic table. Can you remember why? As a result electronegativity is a periodic property, so for example, the halogens (Group 7a elements) are all highly electronegative. ...
Document
... Four electron pairs around an atom assume tetrahedral arrangement. When there are not enough electrons for single bonds the molecule forms multiple bonds and the structure differs. VSEPR theory treats each multiple bond as a single electron group, because it occupies roughly the same region of space ...
... Four electron pairs around an atom assume tetrahedral arrangement. When there are not enough electrons for single bonds the molecule forms multiple bonds and the structure differs. VSEPR theory treats each multiple bond as a single electron group, because it occupies roughly the same region of space ...
lecture slides of chap8
... Radius is defined as one half the distance between the centers of atoms in the molecule. ...
... Radius is defined as one half the distance between the centers of atoms in the molecule. ...
Miss Pang`s 2012 Review
... 16. The atomic number of magnesium is 12. How many protons and valence electrons respectively does magnesium have? A) 12 and 12 ...
... 16. The atomic number of magnesium is 12. How many protons and valence electrons respectively does magnesium have? A) 12 and 12 ...
Silicon vs. Carbon - Coristines
... Carbon has varied hardness levels. It can vary from 0.5 mohs (graphite) to ...
... Carbon has varied hardness levels. It can vary from 0.5 mohs (graphite) to ...
Chapter 2 2012
... Atoms and molecules tend to form three types of chemical bonds: ionic, covalent and metallic. Ionic BondingElectrons from one atom are transferred to another element that has a tendency to accept electrons (IE and EA). ...
... Atoms and molecules tend to form three types of chemical bonds: ionic, covalent and metallic. Ionic BondingElectrons from one atom are transferred to another element that has a tendency to accept electrons (IE and EA). ...
Electronegativity
Electronegativity, symbol χ, is a chemical property that describes the tendency of an atom or a functional group to attract electrons (or electron density) towards itself. An atom's electronegativity is affected by both its atomic number and the distance at which its valence electrons reside from the charged nucleus. The higher the associated electronegativity number, the more an element or compound attracts electrons towards it. The term ""electronegativity"" was introduced by Jöns Jacob Berzelius in 1811,though the concept was known even before that and was studied by many chemists including Avogadro.In spite of its long history, an accurate scale of electronegativity had to wait till 1932, when Linus Pauling proposed an electronegativity scale, which depends on bond energies, as a development of valence bond theory. It has been shown to correlate with a number of other chemical properties. Electronegativity cannot be directly measured and must be calculated from other atomic or molecular properties. Several methods of calculation have been proposed, and although there may be small differences in the numerical values of the electronegativity, all methods show the same periodic trends between elements. The most commonly used method of calculation is that originally proposed by Linus Pauling. This gives a dimensionless quantity, commonly referred to as the Pauling scale, on a relative scale running from around 0.7 to 3.98 (hydrogen = 2.20). When other methods of calculation are used, it is conventional (although not obligatory) to quote the results on a scale that covers the same range of numerical values: this is known as an electronegativity in Pauling units. As it is usually calculated, electronegativity is not a property of an atom alone, but rather a property of an atom in a molecule. Properties of a free atom include ionization energy and electron affinity. It is to be expected that the electronegativity of an element will vary with its chemical environment, but it is usually considered to be a transferable property, that is to say that similar values will be valid in a variety of situations.On the most basic level, electronegativity is determined by factors like the nuclear charge (the more protons an atom has, the more ""pull"" it will have on electrons) and the number/location of other electrons present in the atomic shells (the more electrons an atom has, the farther from the nucleus the valence electrons will be, and as a result the less positive charge they will experience—both because of their increased distance from the nucleus, and because the other electrons in the lower energy core orbitals will act to shield the valence electrons from the positively charged nucleus).The opposite of electronegativity is electropositivity: a measure of an element's ability to donate electrons.Caesium is the least electronegative element in the periodic table (=0.79), while fluorine is most electronegative (=3.98). (Francium and caesium were originally assigned both assigned 0.7; caesium's value was later refined to 0.79, but no experimental data allows a similar refinement for francium. However, francium's ionization energy is known to be slightly higher than caesium's, in accordance with the relativistic stabilization of the 7s orbital, and this in turn implies that caesium is in fact more electronegative than francium.)