1. For HF and HBr, the partial positive charge on H atom is 0.29 and 0.09, respectively. Use electronegativities (EN) to explain why the partial charge on H in HF is more positive than the partial charge on H in HBr.

The partial charge on H in HF is more positive than the partial charge on H in HBr because the electronegativity of F is more than the electronegativity of Br.

The HF and HBr form ionic bonds. The bonds have been formed by the transfer of electrons between the two atoms.

The more the electronegative the atom, the more charge has been exerted by the molecule onto the adjoining element.

In the periodic table, the electronegativity decreases down the group. The electronegativity of F is much larger than the electronegativity of Br. Therefore the partial charge exerted to H in HF has been more than the charge exerted in the HBr molecule.

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Electro negativity decreases down the group

Explanation:

One of the known periodic trends is that electro negativity decreases down the group but increases across the period. The electro negativity of fluorine is 3.98 on the Pauling's scale while that of bromine is 2.96. Hence the magnitude of charge separation and degree of partial positive charge on hydrogen in HF must be much greater than that of HBr to a large extent due to the significant difference in electronegativity in HF compared to HBr.

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

according to the u.s. department of agriculture, the label of "certified organic" comes with a set of highly regulated standards for environmental stewardship and resource conservation. some of these include maintenance and improvement of soil quality, prevention of ground and surface water contamination, greenhouse gas regulation, encouragement of biodiversity and conservation of water and energy (see references 1). organic practices integrate natural methods such as mulching, plant diversity, native and adapted plants, crop rotation and the introduction of beneficial insects to control pests without synthetic pesticides.

environmental implications of pesticides

synthetic pesticides ensure high crop yields. while effective in achieving this goal, pesticides contaminate soil, air, ground and surface water, as well as the plants and animals that come into contact with these contaminated sources. freshwater and marine organisms are particularly susceptible to pesticides through agricultural runoff. pesticides also reduce soil fertility (necessitating the use of synthetic fertilizers) and can travel far from the original source, contaminating water and air hundreds of miles from the location of application (see references 2).

health implications of organics

although a subject of particular debate, many recent findings show that organic food is healthier than conventionally grown food. according to the usda, an extensive european union-funded study found that organically grown foods contain more beneficial compounds, such as the vitamins and antioxidants needed to combat many diseases (see references 5). organic milk, meat and eggs are regulated to ensure they are free of hormones administered to conventional livestock and poultry.

health implications of pesticides

pesticides affect human health in three ways: through skin contact, inhalation and ingestion. acute and long-term exposure to pesticides can cause serious health problems for farmers who apply them. the majority of other people are affected by drinking contaminated water and eating contaminated marine life (see references 3). pesticides have been linked to neurological disorders, endocrine and reproductive disorders, immune system deficiencies and cancer. according to the world health organization, acute pesticide poisoning (app) is responsible for significant annual mortality, especially in developing nations (see references 4).

other important considerations

not every small farm or business owner can afford the costly certification process required to be considered "certified organic," even if the farm is not using chemicals. "transitional" farms include those that once used chemicals and are now transitioning to organic-only production. in addition, though organic farming methods offer obvious environmental benefit, an organic apple shipped from around the world creates a different set of environmental problems. locally grown food (particularly locally grown, organic food) is key in sustainable food production.