![]() ![]() We will also see how we can capture XPath of a few tricky web elements while performing Selenium automation testing. #Examples of elements how to#In this Selenium testing tutorial, we will learn about the types of XPath in Selenium and how to write basic and complicated XPath. Learn more about what Is Selenium?Īlthough XPath is not the only technique that Selenium offers to locate any element, XPath provides an option to search a web element dynamically, and hence, gives the flexibility to tweak any locator to support your requirement. Now, when I started with my first Selenium automation framework, XPath proved to be a boon when it came to capturing web elements. However, to implement a framework using Selenium, the first step is to locate any web element. Selenium is a free, open-source test automation framework that can help us test an application across different platforms and browsers. For more in-depth resources, check out our content hub on Selenium Locators Tutorial. Thus, the atomic radius increases from top to bottom as we go through the groups of the Periodic Table and decreases from left to right as we go through their periods.This article is a part of our Content Hub. The opposite is true for elements with high atomic radii: they give up their outer electrons easily. When the atomic radius is small, the electrons in the outermost level of the cloud are strongly attracted to the nucleus, so they do not give up easily. The different elements have varying atomic radii and, as the number of protons in the nucleus increases, the greater the attraction that the nucleus exerts on the electrons, so the atomic radius tends to decrease. In addition, the color in which the symbol of the element is represented signifies its state of aggregation (depending on the representation used in each Periodic Table). ![]() Below the symbol of the element appears its name and above, to the left, its relative atomic mass. First, in the center of each box, its universal symbol, which consists of one or two letters, is highlighted in large type (by convention, if there are two letters, the first is written in upper case and the next in lower case).Ībove and to the left appears in small type its atomic number, which is the one that indicates the number of protons that the element has. How are the elements presented in the Periodic Table?Įach chemical element is characterized in the Periodic Table using certain symbology. These properties are important because they allow predicting their behavior, reactivity, etc. Chemical elements have properties such as boiling and melting points, electronegativity, density and ionic radius, among others. Some isotopes are not stable (radioactive), that is, they disintegrate in a certain time, emitting certain particles (neutrons, photons, alpha particles, among others) and generate other stable or radioactive isotopes. This means that each isotope atom has the same number of protons (which implies that it belongs to the same chemical element) and a different number of neutrons. ![]() the same chemical element, for example, hydrogen (H), can have several isotopes (1H, 2H, 3H). Many of these elements have stable or radioactive isotopes, i.e. The main groups that can be found in this table are:Īlkali metals (Group 1), alkaline earth metals (Group 2), the scandium family, which includes the earths and actinides (Group 3), the titanium family (Group 4), the vanadium family (Group 5), the chromium family (Group 6), the manganese family (Group 7), the iron family (Group 8), the cobalt family (Group 9), the nickel family (Group 10), the copper family (Group 11), the zinc family (Group 12), earth elements (Group 13), carbonaceous elements, in this group is carbon, which forms the basis of life on Earth (Group 14), nitrogenaceous elements (Group 15), amphigenic elements, including oxygen, a fundamental element for the respiration of living beings (Group 16), halogenous elements (Group 17) and noble gases (Group 18). The Periodic Table is composed of 18 groups (columns) and 7 periods (rows), in which the chemical elements are placed. They are all gathered, classified and organized according to many of their properties in a graphical scheme known as the Periodic Table of the Elements, which was originally created by the Russian chemist Dimitri Mendeleyev in 1869. The first definition of an element was introduced by Lavoisier in the Traité Élémentaire de Chimie, in 1789. For example: sulfur, boron, chromium, tin. For this reason, it can be said that an element is any matter made up of atoms of one and the same kind, that is, atoms that have the same atomic number (equal number of protons), even if they have different atomic masses. Elements are a type of matter that by no procedure or chemical reaction can be reduced or decomposed into other simpler elements. ![]()
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