...INTRODUCTION GROUP 2 (THE ALKALINE EARTH METALS) These elements are categorized as group 2 because they have two electrons in their outer shell, therefore each element in this group will lose two electrons in order to form a 2+. According to RSC (n.d) group 2 elements are all metals with silver-white color. ELEMENT | SYMBOL | No. OF ELECTRONS | Beryllium | Be | 2,2 | Magnesium | Mg | 2,8,2 | Calcium | Ca | 2,8,8,2 | Strontium | Sr | 2,8,18,8,2 | Barium | Ba | 2,8,18,18,2 | TRENDS IN ATOMIC RADIUS The graph below shows that the atomic radius of group 2 elements increases as it descends down the group. (Jim Clark, 2002) “The radius of an atom is governed by the number of layers of electrons around the nucleus due to the pulling power of the nucleus to the outer electrons”(jim clark,2002). For example: Be 1s2 2s2 Mg 1s22s22p63s2 In both atoms the two outer electrons feel a net pull of 2+ from the nucleus. (Jim Clark, 2002) ...
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...their conductivity. One propertity which effects how they will chemically react is the number of electrons which they have in their valency shell. Sodium has one electrons in its’ outter most shell, leaving it eager to fulfill the octet rule. Where as Argon is a noble gas and so it has a full outter most shell, therefore it has no desire to react to fulfill the octet rule. Another is the first ionisation energy. (d) B & G, Beryllium and Calcium. Beryllium has a first ionisation energy of 899.5kJ/mol. Calcium has a first ionisation energy of 589.8kJ/mol. This in turn means that more energy is required to remove an electron from an atom in a gaseous state for Beryllium than for Calcium. The energy required is dependent on the atomic radii. This is as the further away the valence electrons are the weaker the attraction is between the nuclei and the valence electrons. We can see that this is so if we look at radius of Beryllium and Calcium. Beryllium has an atomic radii of 112pm, whereas Calcium has an atomic radii of 194pm. This correlates with the fact that Beryllium has a larger first ionisation energy. Q3. (i) KCl is an ionic compound, as ionic bounds occur between a metal and non-metal. S is a non-metal, as it is non-conductive, brittle and lacks lustre. CO2 is a covalent compound, as a covalent bond is between two non-metals. Mg is a metal as it is conductive and lustre. (ii) (a) NaCl has an ionic bond. Na was oxidised, losing 1 electron and turn into cation Na1+. Cl was reduced...
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...Alkali metals Cations occur in wide variety of important chemicals The metals are all very reactive when pure – strongly reducing Their cations (with the exception of lithium) have low charge densities – often leads to good solubility and an ability to stabilize anions that can not be formed along with any other cation Alkali metal physical properties Element Li Na K Rb Cs Density (gcm-3) 0.53 0.97 0.86 1.53 1.87 Melting point (oC) 180 98 64 39 29 ∆Hatm (kJmol-1) 162 108 90 82 78 1 Reactivity towards Bronsted acids The alkali metals react even with weak Bronsted acids such as water – The rate of reaction depends upon the acidity of the medium 2Na + 2H2O 2Na + 2EtOH 2Na + 2NH3 2NaOH + H2 2NaOEt + H2 2NaNH2 + H2 – very slow reaction in absence of catalyst Alkali metals and liquid NH3 Alkali metals react very slowly with liquid ammonia – however, they typically dissolve rapidly in ammonia to form highly colored solutions Na(s) --(ammonia)--> Na(am) + e-(am) – fast 2e-(am) + 2NH3 2NH2- + H2 – slow in absence of catalyst 2 Sodide anions and electrides 2Na(s) + C12H24O6 [Na(C12H24O6)]+Na– complexing or chelating agent is used to stabilize the cation » Na- is the sodide anion. It is the most stable alkalide ion Other complexing agents have been used to form solid salts where e- is the anion – electrides Lithium Lithium is the most reducing of all the alkali metals – but not the most reactive Unlike the other alkali metals it reacts with nitrogen to form a nitride Used...
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...Introduction…….………………………………………………………………………………….3 History……………………………………………………………………………………………..3 Background………………………………………………………………………………...........3-5 Who OSHA Covers………………………………………………………………………..4 Who OSHA Doesn’t Cover……………………………………………………………..4-5 Worker Rights……………………………………………………………….…………….5 Regulations “Standards”………… ……………………………………………….............5 Organizational Profile………………………………………………….………………………..6-7 National……………………...…………………….………………………………………6 Regional………………………………………………...…………………………………6 Advisory Committee’s……………………..……………………………………………6-7 Annual Report..………………………………………………………………………………….7-8 Controversies………..…………………………………………………………………………..8-9 Regulations and Enforcement Policies…………..………………………………..…….8-9 OSHA Inspectors and Beryllium………………………………..…..…………………….9 Conclusion…………………………………………………………………..…………………9-10 References………………………………………………………………………………………..11 Introduction Occupational Safety and Health Administration (OSHA) is a dependent agency under the United States Department of Labor. According to OSHA, congress enacted the Occupational Safety and Health Act of 1970, which enabled the Occupational Safety and Health Administration (OSHA). “ OSHA’s mission under the OSH Act of 1970 is to assure safe and healthful conditions for working men and women by setting and enforcing standards and providing training, outreach, education and compliance assistance, [in order] to help employers and employees reduce on the job injuries, illnesses and deaths.” (All About OSHA) ...
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...which allows users to charge the phone anywhere the sun is shining — and in India, that’s most places. The Guru is the first solar mobile phone to hit the market, and, at $60, it’s designed to be affordable as well. One hour of solar charging provides 5 to 10 minutes of talk time. Samsung Blue Earth – Blue Earth is a gorgeous green touch phone that has a full solar panel on its back which can generate enough power to charge the phone. And yes – the gadget is still small enough to fit in your pocket! The body of the phone is made out of recycled water bottles and has no brominated flame retardants, beryllium and phthalates – all incredibly toxic substances. That goes for the charger as well, which also meets the newer standby mode energy efficiency ratings. The body of the phone is made out of recycled water bottles and has no brominated flame retardants, beryllium and phthalates – all incredibly toxic substances. That goes for the charger as well, which also meets the newer standby mode energy efficiency ratings. Competitor’s Weakness – It takes 40 hours to get a full charge — a number that will most likely come down as the technology is refined. With free electricity, the phone will save users money and make them more available for economic...
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...found to have other, more important uses. Calcium is essential for human and animal nutrition as it is a main component of teeth and bones. Our skeletons get there rigidity from calcium phosphate. Calcium is also necessary for plant growth. Calcium compounds are used in making lime, limestone, bricks, cement, glass, paint, paper and fireworks. The Alkali Earth Metals Calcium belongs to the alkali earth metal group. This group of elements are quite reactive (though not as reactive as the alkali earth metals.) as they have “over-complete” outer shells and only need to lose two electrons wen reacting to become stable. Other elements in this group include beryllium, magnesium, strontium, barium and radium. Beryllium (Be) is a rare metal that is white-grey-metallic in colour. Its atomic number is 4. Beryllium is extremely rigid and is relatively transparent on x-rays. Its main use is in the manufacture of telecommunications...
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...1. Give an everyday example that illustrates the difference between acceleration and velocity. Give an example of uniform and accelerated motion. An everyday example of the difference between acceleration and uniform motion would be for acceleration driving a car down a long straight road, the speedometer is not moving, the needle is on 40 mph, your moving at a constant speed, but the needle isn’t stationary on the speedometer scale because maybe your foot is either on the gas or brake and your speed is changing and your are accelerating. An example of uniform and accelerated motion would be a driving are car down a highway, accelerating to get to the speed limit which is 75 and uniform motion would be a car is cruising at 75 miles at that constant speed. 2. What determines the difference between scientific knowledge and non-scientific knowledge? What determines the different between scientific knowledge and non-scientific knowledge is that scientific knowledge is based on a body of techniques for investigating phenomena, acquiring new knowledge and integrating previous knowledge consisting of the data collected through observation, experimentation, and formulation and testing the hypothesis, basically using the scientific method to perform the results. Scientific knowledge is the knowledge that has been gained from analyzing evidence. Non-scientific knowledge is the gathering of information by people or institutions that do know use the scientific method. 3. Why do...
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...7) Find valency of Fluorine and Beryllium atoms? Answer: Keep in view, the follwing two rules to find valency of an element i.e. Rule-1: If the outermost shell of an atom of the element contains electrons less than or equal to 4, the valency of the atom is equal to the number of valence shell electrons. Rule-2: If the outermost shell of an atom contains electrons more than 4, the valency of an atom is then given by subtracting the valence shell electrons from 8. Electronic configuration of Fluorine is 2, 7. Here, valence electrons are 7 Hence, valecny of Fluorine is = 8 _ 7 = 1 Electronic configuration of Beryllium is 2, 2. Thus, there are 7 valence electrons Hence, valency of Beryllium is 1. 8) Why Neon and Argon have zero valency? Answer: Tendency of an element to gain or lose electron in order to complete its octet is known as its valency. Neon and Argon have completely filled outermost shell, i.e. they have octet configuration, so they have no need to gain or lose electrons (see their electronic configurations...
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...as well as following proper convention for symbols. We moved on to reviewing an example for writing word equations as well as percent composition. During the percent composition you ensured we understand each step must be included for full point in case of an error during our procedure. We finished the eChat reviewing empirical formulas as well molecular formulas and discussing stoichiometry and the chemical recipe of “club house stoichometry”. We worked through some questions of stoichometry as well as mass stoichometry. 2. What skills or concepts did you learn by participating in this eChat? The skills and concepts I learned by participating in this eChat were related to writing word problems. Part b, Question 1 stated “when beryllium chloride reacts with silver...
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...exhibit similar properties. Similar to magnesium nitrate, lithium nitrate decomposes on heating to produce lithium oxide, oxygen and nitrogen dioxide. 2LiNO3 (s) Li2O (s) + 2NO2 (g) + 1/2 O2 (g) Mg(NO3)2 (s) MgO (s) + 2NO2 (g) + 1/2 O2 (g) Lithium hydroxide and carbonate decompose to form oxides and the corresponding gases. 2LiOH (s) Li2O (s) + H2O (g) Mg(OH)2(s) MgO(s) + H2O(g) Li2CO3 (s) Li2O (s) + CO2 (g) MgCO3 (s) MgO (s) + CO2 (g) Diagonal Relationship between Be and Al There are many similarities between Be and Al. When dissolved in water, Be2+(aq) and Al3+ (aq) undergo hydrolysis to produce acidic solutions. Although beryllium and aluminium are metals, their chlorides are covalent in character i.e. BeCl2 and AlCl3 are simple covalent compounds. Both beryllium and aluminium can form amphoteric oxides and hydroxides. Beryllium does not form a stable carbonate while aluminium carbonate does not even exist. Thermal Decomposition of Lithium Nitrate Due to the diagonal relationship between Li and Mg, it is expected that the thermal decomposition of lithium nitrate would resemble that of magnesium nitrate. A simple experiment may be performed to confirm this hypothesis using the following apparatus: 100 cm3 gas syringe, delivery tube, boiling tube and Bunsen burner. If decomposition follows Group I chemistry, 2LiNO3(s) 2LiNO2(s) + O2 (g) -----(1) If decomposition follows Group II chemistry, 2LiNO3 (s) Li2O (s) + 2NO2 (g) + 1/2 O2 (g) -----(2) Preliminary...
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...Chapter 10 Outline The Shapes of Molecules Introduction Whether we consider the details of simple reactions, the properties of synthetic material, or the intricate life-sustaining processes of living cells, molecular shape is a crucial factor. 10.1 Depicting Molecules and Ions with Lewis Structures Lewis structures, also called electron-dot structures or electron-dot diagrams, are diagrams that show the bonding between atoms of a molecule, and the lone pairs of electrons that may exist in the molecule. A Lewis structure can be drawn for any covalently-bonded molecule, as well as coordination compounds. Using the Octet Rule to Write Lewis Structures The octet rule tells us that all atoms want eight valence electrons (except for hydrogen, which wants only two), so they can be like the nearest noble gas. Use the octet rule to figure out how many electrons each atom in the molecule should have, and add them up. The only weird element is boron - it wants six electrons. Lewis Structures for Molecules with Single Bonds The atoms share a pair of electrons, and that pair is referred to as a bonding pair. The pairs of electrons which do not participate in the bond have traditionally been called "lone pairs". A single bond can be represented by the two dots of the bonding pair, or by a single line which represents that pair. The single line representation for a bond is commonly used in drawing Lewis structures for molecules. · Hydrogen atoms form one bond. · Carbon...
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...selected. Since the spacecraft would not decelerate, upon reaching Barnard's Star, Daedalus would carry 18 autonomous sub-probes that would be launched between 7.2 and 1.8 years before the main craft entered the target system. These sub-probes would be propelled by nuclear-powered ion drives and would carry cameras, spectrometers, and other sensory equipment. The sub-probes would fly past their targets, still traveling at 12% of the speed of light, and transmit their findings back to the Daedalus' second stage, mothership, for relay back to Earth. The ship's payload bay containing its sub-probes, telescopes, and other equipment would be protected from the interstellar medium during transit by a beryllium disk, up to 7 mm thick, weighing up to 50 tonnes. This erosion shield would be made from beryllium due to its lightness and high latent heat of vaporisation. Larger obstacles that might be encountered while passing through the target system would be dispersed by an artificially generated cloud of particles, ejected by support vehicles called dust bugs about 200 km ahead of the vehicle. The spacecraft would carry a number of robot wardens capable of autonomously repairing damage or malfunctions. So like in the future we could send people to go inside daedalus spacecraft and send them to a local galaxy where they may not back to us because they might not have enough fuel to get them back home so they would die from starvation or dehydration. Alcubierre drive is a speculative idea based...
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...Why nuclear power will never supply the world's energy needs Nuclear power plant in Dukovany, Czech Republic. Image credit: Petr Adamek. (PhysOrg.com) -- The 440 commercial nuclear reactors in use worldwide are currently helping to minimize our consumption of fossil fuels, but how much bigger can nuclear power get? In an analysis to be published in a future issue of the Proceedings of the IEEE, Derek Abbott, Professor of Electrical and Electronic Engineering at the University of Adelaide in Australia, has concluded that nuclear power cannot be globally scaled to supply the world’s energy needs for numerous reasons. The results suggest that we’re likely better off investing in other energy solutions that are truly scalable. As Abbott notes in his study, global power consumption today is about 15 terawatts (TW). Currently, the global nuclear power supply capacity is only 375 gigawatts (GW). In order to examine the large-scale limits of nuclear power, Abbott estimates that to supply 15 TW with nuclear only, we would need about 15,000 nuclear reactors. In his analysis, Abbott explores the consequences of building, operating, and decommissioning 15,000 reactors on the Earth, looking at factors such as the amount of land required, radioactive waste, accident rate, risk of proliferation into weapons, uranium abundance and extraction, and the exotic metals used to build the reactors themselves. "A nuclear power station is resource-hungry and, apart from the fuel, uses many...
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...extraction * Acid–base reaction * Acid–base titration * Dissociation constant * Acidity function * Buffer solutions * pH * Proton affinity * Amphoterism * Self-ionization of water * Acid strength | Acid types | * Brønsted · * Lewis · * Mineral · * Organic · * Strong · * Superacids · * Weak | Base types | * Brønsted · * Lewis · * Organic · * Strong · * Superbases · * Non-nucleophilic · * Weak | * v · * t · * e | In chemistry, an amphoteric species is a molecule or ion that can react as an acid as well as a base.[1] The word is derived from the Greek word amphoteroi (ἀμφότεροι) meaning "both". Many metals (such as zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. Amphoterism depends on the oxidation state of the oxide. One type of amphoteric species are amphiprotic molecules, which can either donate or accept a proton (H+). Examples include amino acids and proteins, which have amine and carboxylic acid groups, and self-ionizable compounds such as water and ammonia. Ampholytes are amphoteric molecules that contain both acidic and basic groups and will exist mostly as zwitterions in a certain range of pH. The pH at which the average charge is zero is known as the molecule's isoelectric point. Ampholytes are used to establish a stable pH gradient for use in isoelectric focusing. Contents [hide] * 1 Amphoteric oxides and hydroxides[2] * 2 Amphiprotic...
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...Austin Eisele Mr. Watson 11 CPLA 4 March 2013 Why Smoke Have you ever tried a cigarette or been around someone who has? Many people smoke because of stress in their lives, Post Traumatic Stress Disorder, and peer pressure. Smokers have a feeling of relief when they start the cigarette and when they finish. The majority of smokers try to quit but only 50% succeed in quitting. My whole life I have lived with at least two smokers in my family so I experience second hand smoke majority of my life. Many people don’t realize the chemicals in the cigarette are all hazardous and dangerous. All cigarettes have Polonium-210 a radioactive chemical element and Cadmium, Beryllium a toxic metal. These chemicals are the main causes of cancer in cigarettes from there known 250 chemicals. Smoking causes many diseases from cancer to aortic aneurysm (a balloon-like bulge in an artery in the chest). Pregnancy smoking can causes pre-mature birth and an abnormally low birth weight. Women who end up smoking before or after their pregnancy increase the chance of their child getting Sudden Infant Death Syndrome. Smoking causes around 440,000 premature deaths every year in the United States. Smoking is the leading cause of premature, preventable death in this country. The cancers that smoking causes acute myeloid leukemia, bladder cancer, cancer of the cervix, cancer of the larynx (voice box). Acute myeloid leukemia is a cancer of the blood and bone marrow and can get worse if left untreated...
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