For example, the molecule acetone is made of carbon, hydrogen, and oxygen. Therefore, it has the chemical formula CH3 2O. Why do atoms form molecules? It all comes down to those positively and negatively charged subatomic particles in an atom. If a proton or electron is lost, an atom can become negatively or positively charged. When this happens, an atom becomes unstable. Well, atoms like balance. Therefore, when an atom becomes negatively or positively charged, they can attract one another to become balanced again.
For example, they might share an electron to form a chemical bond. This can be a single bond such as in the case of ammonia NH3. Electrostatic forces hold atoms together in molecules—like the two hydrogen atoms held together in H2 gas. Electrostatic forces also hold electrons and protons together in the atom. The attraction between negatively charged electrons and positively charged protons in an atom give the atom its structure. The strong force holds neutrons and protons together in the nucleus.
This force got its name because it is strong enough to overcome the force of the positively charged protons repelling each other. The number of electrons and protons in an atom determines its chemical properties. Chemical properties include the specific ways that atoms and molecules react and the energy that they release or use in these reactions. One hundred million ,, hydrogen atoms put side-by-side equals about a centimeter.
This means it would take about one hundred billion ,,, protons or neutrons put side-by-side to equal a centimeter. This means that it would take one hundred trillion ,,,, electrons put side-by-side to equal a centimeter! The subatomic particles in an atom determine the properties of the atom. Some atoms exist naturally as neutral, or uncharged, atoms. An uncharged atom is electrically neutral because electrons and protons have opposite charges of equal sizes. When the number of protons and electrons in an atom are same, the charges cancel out, or counteract each other.
Every atom of a particular element has the same number of protons. The atomic number is equal to the number of protons in an element. On the periodic table, the atomic number is usually given as the whole number above the symbol for the element see Fig.
For example, hydrogen H has an atomic number of one 1. This means a hydrogen atom has one proton. If a hydrogen atom is neutral, it must also have one electron.
An oxygen atom O has an atomic number of eight 8. This means a neutral oxygen atom has eight protons and eight electrons. The element Actium Ac has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom. Table 2. Neutrons affect the mass of an atom and play a role in the stability of atoms. Unlike protons, the numbers of neutrons in elements varies. For example, most hydrogen atoms have no neutrons, but a few have one neutron, and some rare hydrogen atoms have two neutrons.
Most helium atoms have two neutrons, but some have three neutrons. The periodic table Fig. In Fig. In Figure 2. The periodic table has three prominent features. First, the periodic table is arranged in horizontal rows, which are called periods. During lockdown, teachers worked so hard to create engaging remote resources.
Scientists dispel the theory that sunlight exposure simply fragments macroplastics that persist in the environment, but what are the implications for the environment? Introduce the study of molecules containing carbon atoms to your students with these many different contexts.
Observation is a key skill for budding chemists. This is how to develop it with your younger students. Site powered by Webvision Cloud. Skip to main content Skip to navigation. Catherine Smith suggests ideas, activities and resources for your classroom.
In your class. Take-home points Particles can be atoms, molecules or ions. The term molecule is often used incorrectly to refer to any type of chemical compound. A molecule is a neutral particle made of two or more atoms bonded together. Take care with your own language, especially when referring to compounds formed during chemical reactions. Make the distinction between each particle type explicit. Give students the opportunity to organise their understanding of the different particle types with Venn diagrams.
A good understanding of the different particle types will help students when they study structure and bonding at 14— Download all. Topics Atoms and bonds Resources. Related articles. News Cooling homes with an endothermic reaction TZ Looking at the use of ammonium nitrate in a new and renewable cooling process. What is Molecule? Main Differences Between Atom and Molecule An atom is the smallest particle of any element, whereas, a molecule is formed when two or more atoms are held together with the help of a chemical bond.
It is possible for atoms to either exist or not exist independently. However, molecules always exist independently or in a free state. It is not possible to break down atoms any further.
On the other hand, molecules can be broken down into atoms of either similar or different elements. The nucleus, comprising of neutrons and protons, along with electrons together form an atom. Molecules, on the other hand, comprise of a minimum of two atoms that may either be identical or different and held together by a chemical bond.
Atoms are always shaped spherical ad molecules that may either be angular or rectangular or linear in shape. Atoms happen to be highly reactive. They can easily participate in any chemical reaction and do not decompose further into any subatomic particles.
However, molecules are comparatively less reactive and do not participate in any chemical reaction. Molecules comprise of two or even more atoms that are bound together by a chemical bond.
0コメント