Definition of Extended Families Today, the era of the nuclear family is often glamorized, complete with mom in the kitchen, dad out earning the paychecks, and the kids building a tree house or hosting a stuffed animal tea party.
Non-metals Non-metals are the elements in groups of the periodic table. Non-metals are not able to conduct electricity or heat very well.
As opposed to metals, non-metallic elements are very brittle.
The non-metals can be gases, such as oxygen and solids, such as carbon. The non-metals have no metallic luster, and do not reflect light. Halogens The halogens are five non-metallic elements found in group 17 of the periodic table. All halogens have 7 electrons in their outer shells, giving them an oxidation number of These elements have an oxidation number of 0.
This prevents them from forming compounds readily. All noble gases have 8 electrons in their outer shell, making them stable and highly non-reactive. Lanthanide Series The Lanthanides consist of the elements in the f-block in the sixth period of the periodic table.
They are soft metals, all naturally occur except for Promethium Rare earth elements which are useful for their metallurgical properties in alloy form are composed of the lanthanide series plus Scandium and Yttrium.
Actinides Series The Actinides series consist of the elements in the f-block in the seventh period of the periodic table. All the elements of Actinides series are radioactive and most are synthetic, that is, human-made.
All have a silvery or silvery-white luster in metallic form.
Periodic Table Trends When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties. Some of these properties include atomic radius, electronegativity, ionization energy and metallic characteristics.
Factors affecting these properties include the number of protons in the nucleus, the distance from the nucleus and amount of shielding inner electrons provide to the valence electrons. Atomic radius The atomic radius is a somewhat imprecise measure that can refer to the mean distance from the center of the nucleus to the boundary of the surrounding electron cloud.
We can determine the radius by dividing the distance between two bonded atoms in half. Depending upon the type of bond we can obtain very different values. If the bond is covalent it is called a covalent radius. If the bond is ionic it is called an ionic radius. The Atomic radius tend to decrease when moving across a period from left to right.
As we move across a period electrons are added to the same energy level and protons are added to the nucleus; increasing the effective nuclear charge and pulling the electrons closer to the nucleus.
The Atomic radius tend to increase when moving down a group from top to bottom.
As we go down a group additional energy levels are added; and each subsequent energy level is further from the nucleus. Electronegativity Electronegativity is the tendency of an atom to attract electrons. It cannot be measured directly and needs to be computed from other atomic properties.
The Pauling scale is a dimensionless quantity developed by Linus Pauling used to describe the electronegativity of an atom. The two key factors in determining electronegativity are its atomic number and radius.
Fluorine has the highest electronegativity and francium the lowest. If the electronegativity difference between two atoms is very large, then the bond type tends to be more ionic, if the difference in electronegativity is small then it is a nonpolar covalent bond.
Ionization energy The first ionization energy is the energy it takes to remove an electron from a neutral atom in gaseous phase.Explore a detailed timeline of World War Two - the causes, events, soldiers and its aftermath. Discover facts about what happened during the most destructive war in history.
Abstract. The tuberal nucleus (TN) is a surprisingly understudied brain region. We found that somatostatin (SST) neurons in the TN, which is known to exhibit pathological or cytological changes in human neurodegenerative diseases, play a crucial role in regulating feeding in mice.
The Governments Make a Move The governments went to work shortly after the cloning of Dolly. They wanted to take control and make laws before anything drastic could ever happen.
Several ethics committees were asked to decide whether scientists should be allowed to try to clone humans. Cochlear Family is a program we created to help guide you in this hearing journey. By simply activating your free membership, you'll have access to everything you'll need to stay up-to-date and informed about your device.
The discs are pads that serve as "cushions" between the vertebral bodies, which minimize the impact of movement on the spinal column. Each disc is designed like a jelly donut with a central softer component (nucleus pulposus). Customer Service Nucleus consultants understand the importance of delivering superior customer service and the personal touch.
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