Periodic Table

The halogens, located in Group 17 (Group VIIA), tend to have seven valence electrons. They require only one more electron to achieve a stable octet configuration, making them highly reactive.

One or two letters are used to represent the name of each element.

The metals and non-metals are separated by a "stair-step" pattern that begins between polonium and astatine and moves up/left to boron. Most periodic tables display this stair-step as a bold line, or a different color, or something else easy to spot. Generally speaking, the metals are everything to the left of the stair-step, and the non-metals are everything to the right. The small handful of elements that "ride" the stair-step are called metalloids. Metalloids can have properties of both metals and non-metals.

the metal that is liquid at room temperature is mercury

Dmitri Mendeleev worked alone while working on the Periodic Table and the Periodic Law. He stayed in close contact with other scientists around the globe, however, and received information and data that they had collected, and added it to his own notes to create a more accurate and agreeable set of data to help him arrange the elements.

Firstly, helium does NOT belong to group 8. In the periodic table used until around the 1960s, helium belonged to group zero. Iron cobalt, and nickel families shared group VIII. In the modern, iupac sanctioned periodic table, the noble gas family -- helium, neon, etc. -- are in group 18.

I think the reason your teacher (? or textbook, or whoever) has asked this question is because all of the other noble gases have 8 electrons in their outermost shell, while helium has only 2.

There is no specific chemical element symbol for salinity. Salinity refers to the concentration of salts in water, typically measured in parts per thousand (ppt) or practical salinity units (PSU).

Everything on and within the Earth, including the molecules that make up you, me, and everyone we have ever heard about and that will ever be, came from the heart of ancient stars, which more than 5 billion years ago exploded in interstellar space. That matter eventually coalesced into our Solar System. Some of it became our sun, some of it wanders our solar system as asteroids, and some of it formed a planet that would be called Earth. We are star dust.

Calcium=Ca=Atomic number 20

9+11=20

The main elements found in fertilizers are nitrogen (N), phosphorus (P), and potassium (K). These elements are essential for plant growth and development. Other elements, such as calcium, magnesium, and sulfur, may also be included in fertilizers to improve soil quality and plant nutrition.

There is no element with the symbol O5 on the periodic table. Oxygen has the symbol O and is located in group 16, period 2 of the periodic table.

The element with the highest atomic volume is francium, which is a highly reactive alkali metal. Francium has the largest atomic radius of all the elements, leading to a high atomic volume.

Iron stands for the element with the chemical symbol Fe on the periodic table.

The chemical symbol for the element iron is Fe, from the latin word for iron "ferrous."

No, Dmitri Mendeleev did not know about protons. The concept of protons was not discovered until later in the 20th century, after Mendeleev's time. Mendeleev is most famous for creating the periodic table of elements.

Actinoids family contain: Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lw.

The two rows of metals that appear at the bottom of the periodic table are the lanthanides and actinides. They are known as the inner transition metals and are placed below the main body of the periodic table to keep the table size manageable.

At-Astatine Because it is the 85th element of the periodic table. That means that it has 85 protons and 85 electrons

The modern periodic table organizes elements based on their atomic number and similar chemical properties, providing a systematic way to study and understand relationships between elements. It helps scientists predict an element's properties based on its position in the table, enabling them to conduct research more efficiently and make advancements in various fields such as chemistry and materials science.

The number of electron rings in each period of the periodic table corresponds to the period number. For example, in the first period (row), there is only one electron ring; in the second period, there are two electron rings, and so on.

Across the period, the total number of shells remain the same. But, atomic number, i.e., no. of protons and electrons goes on increasing. Protons (positively charged) present in the nucleus exert a nuclear charge towards the electrons (negatively charged) present around the nucleus, and pull the shells toward the nucleus. Hence, when no. of protons increases, nuclear charge also increases and hence it pulls the shells with greater force, and shells get closer to the nucleus. Hence, across the period, atomic size, or the radii go on decreasing.

The atomic size increases within a group in the periodic table due to the addition of energy levels as you move down the group. As you go down a group, each element has one more energy level than the one above it, leading to an increase in atomic size.

Potassium is more reactive in water. This is due to the fact its outer shell is further from the attractive forces of the nucleus and therefore the electron in the outer shell is more easily lost - allowing a reaction to take place.