For the same reason electronegativity – the degree to which an element tends to gain electrons – increases from left to right. More protons means that electrons are pulled in more tightly toward the nucleus. Moving from the left side of the period to the right, the atomic radius becomes smaller because each element has one additional proton and one additional electron. The horizontal rows of the table are called periods. This is important because how elements interact and react with each other depends on their ability to lose and gain electrons to make new compounds. But the amount of energy needed to rip off an outer electron decreases going from the top to the bottom because the electrons are farther from the nucleus and not held as tightly. Going from the top of Group I to the bottom, for example, the atomic radii – the distance from the nucleus to the outer electrons – increases. And the properties can be assumed based on the location within the group. Elements in the same group share similar properties. By studying the behavior and trends of Group I elements, we can get a glimpse of how the periodic table is arranged and how to interpret it.Įach of the 18 columns in the table is called a group or a family. I am a chemist who spent his career building new molecules, sometimes using Group I elements. Not only are they very reactive, they are soft and shiny, can easily be cut even with a dull knife and are the most metallic of all known elements. For further dramatic effect, I also placed some potassium into water and astonished everyone with the explosive bluish flames.īecause Group I metals, also known as alkali metals, are very reactive, like the sodium from the rail car or the potassium, they are not found in nature in pure form but only as salts. While on the air I added some sodium to a bit of water in a petri dish and we observed the vicious reaction. A television reporter called me for an explanation of why firefighters were not allowed to use water on the flames bursting from the mangled car. Lithium is the key component of lithium-ion battery technology, which is becoming increasingly more prevalent in electronics.The news broke that a railroad car, loaded with pure sodium, had just derailed and was spilling its contents. Because of its high reactivity, elemental lithium does not occur in nature. In its elemental form, lithium is soft enough to cut with a knife its silvery white appearance quickly darkens when exposed to air. Compared to other metals, it has one of the lowest boiling points. It has the highest specific heat and electrochemical potential of any element on the period table and the lowest density of any elements that are solid at room temperature. The origin of the name Lithium comes from the Greek word lithose which means "stone." Lithium is a member of the alkali group of metals. Lithium was discovered by Johann Arvedson in 1817 and first isolated by William Thomas Brande in 1821. The lithium atom has a radius of 152 pm and a Van der Waals radius of 181 pm. The number of electrons in each of Lithium's shells is and its electron configuration is 2s 1. Lithium (atomic symbol: Li, atomic number: 3) is a Block S, Group 1, Period 2 element with an atomic weight of 6.94. Thin Film Deposition & Evaporation Materials.Additive Manufacturing & 3D Printing Materials.
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