10 Helium Facts - Atomic Number 2 on the Periodic Table

10 Helium Facts - Atomic Number 2 on the Periodic Table Helium is the second element on the periodic table, with atomic number 2 and element symbol He. Its the lightest noble gas. Here are ten quick facts about the element helium. Check the full listing for helium if you would like additional element facts. The atomic number of helium is 2, meaning each atom of helium has two protons.  The most abundant isotope of the element has 2 neutrons. It is energetically favorable for each helium atom to have 2 electrons, which gives it a stable electron shell.Helium has the lowest melting point and boiling point of the elements, so it only exists as a gas, except under extreme conditions.  At normal pressure, helium is a liquid at absolute zero.  It must be pressurized to become a solid.Helium is the second-lightest element.  The lightest element or one with the lowest density is hydrogen. Even though hydrogen typically exists as a diatomic gas, consisting of two atoms bonded together, a single atom of helium has a higher density value. This is because the most common isotope of hydrogen has one proton and no neutrons, while each helium atom typically has two  neutrons as well as two protons.Helium is the second-most abundant element in the universe  (after hydrogen), though it is mu ch less common on Earth.  On Earth, the element is considered a nonrenewable resource.  Helium does not form compounds with other elements, while the free atom is light enough to escape Earths gravity and bleed out through the atmosphere. Some scientists are concerned we might one day run out of helium or at least make it prohibitively expensive to isolate. Helium is colorless, odorless, tasteless, non-toxic, and inert.  Of all the elements, helium is the least reactive, so it does not form compounds under ordinary conditions. In order to bond it to another element, it would need to be ionized or pressurized. Under high pressure, disodium helide (HeNa2), the clathrate-like titanate La2/3-xLi3xTiO3He, the silicate crystobalite He II (SiO2He), dihelium arsenolite (AsO6 ·2He), and NeHe2 may exist.Most helium is obtained by extracting it from natural gas.  Its uses include helium party balloons,  as a protective inert atmosphere for chemistry storage and reactions, and for cooling superconducting magnets for NMR spectrometers and MRI machines.Helium is the second-least reactive noble gas (after neon).  It is considered the real gas that most closely approximates the behavior of an ideal gas.Helium is monatomic under standard conditions. In other words, helium is found as single atoms of the element.Inhaling helium temporarily chan ges the sound of a persons voice. Although many people think inhaling helium makes a voice sound higher, it doesnt actually alter the pitch. Though helium is non-toxic, breathing it can result in asphyxiation due to oxygen deprivation. Evidence of heliums existence came from the  observation of a yellow spectral line from the sun. The name for the element comes from the Greek god of the Sun, Helios.

CIS 206 U2 Discussion Example

CIS 206 U2 Discussion Example CIS 206 U2 Discussion – Coursework Example CIS 206 U2 Discussion CIS 206 U2 Discussion Proper configuration of directory and file permissions is significant in all systems. In Linux operating system, it is equally important to ensure that information security is guaranteed. Though the Linux Operating System are secure by default, it is important that administrators verify that the directory and file permissions of the server are at secure. Additionally, proper configuration of the directory and file permissions ensure that administrators share data in a safe manner (Lewis, 2013). The use of default or fewer restrictive permissions on files or directories poses several threats and attacks to the information contained on Linux servers. With the default settings, attacks that causes deletion of files or overwriting of files may readily occur. Different administrators may also create a symbolic link to any file, and this could cause deletion of data. Additionally, there are certain files that may grant access and special privile ges to the users when there are no restrictive permissions. In an organization, it is imperative to create permission groups. First, the members of the organization must be categorized into three groups based on their permission of accessing directories and files. The groups will include the owner, group and all users. Each of the directories and groups must be assigned three basic permissions. The member who can have the permission to write files must be the administrators of the firm. Depending on the type of organizational information, members of the organization may be granted the access to read and execute commands. In the organizational set-up, the formation of permission groups and assigning of relevant permission type can guarantee the safety of organization files and directories. ReferencesLewis, J. (2013).  Linux utilities cookbook. [Place of publication not identified]: Packet Publishing Limited.