Periodic trends play a big role in how elements act during chemical reactions. There are three main trends to know: reactivity, electronegativity, and ionization energy.
Metals: For metals, reactivity goes up as you move down Group 1, which contains alkali metals. For example, lithium (Li) can react with water, but cesium (Cs) can explode when it reacts!
Nonmetals: For nonmetals, reactivity increases as you move up Group 17, called halogens. Fluorine (F) is the most reactive nonmetal, while iodine (I) is not as reactive.
What is it?: Electronegativity is a way to measure how strongly an atom can pull on electrons in a chemical bond. It uses a scale called the Pauling scale, which goes from 0.7 (Francium) to 4.0 (Fluorine).
Trend: Electronegativity goes up from left to right on the periodic table and goes down as you go down a group. For instance, carbon (C) has an electronegativity of 2.5, while oxygen (O) has 3.5. This means oxygen pulls on electrons more strongly than carbon.
What is it?: Ionization energy is the energy needed to remove an electron from an atom. If an atom has a high ionization energy, it means it holds onto its electrons tightly.
Trend: Ionization energy goes up across a period and goes down down a group. For example, helium (He) has an ionization energy of 24.6 electron volts (eV), while cesium (Cs) has only 3.9 eV.
Knowing about these trends can help us guess how elements will behave in chemical reactions. Reactivity, electronegativity, and ionization energy are important in creating compounds, understanding how bonds form, and figuring out the stability of molecules during reactions.
Periodic trends play a big role in how elements act during chemical reactions. There are three main trends to know: reactivity, electronegativity, and ionization energy.
Metals: For metals, reactivity goes up as you move down Group 1, which contains alkali metals. For example, lithium (Li) can react with water, but cesium (Cs) can explode when it reacts!
Nonmetals: For nonmetals, reactivity increases as you move up Group 17, called halogens. Fluorine (F) is the most reactive nonmetal, while iodine (I) is not as reactive.
What is it?: Electronegativity is a way to measure how strongly an atom can pull on electrons in a chemical bond. It uses a scale called the Pauling scale, which goes from 0.7 (Francium) to 4.0 (Fluorine).
Trend: Electronegativity goes up from left to right on the periodic table and goes down as you go down a group. For instance, carbon (C) has an electronegativity of 2.5, while oxygen (O) has 3.5. This means oxygen pulls on electrons more strongly than carbon.
What is it?: Ionization energy is the energy needed to remove an electron from an atom. If an atom has a high ionization energy, it means it holds onto its electrons tightly.
Trend: Ionization energy goes up across a period and goes down down a group. For example, helium (He) has an ionization energy of 24.6 electron volts (eV), while cesium (Cs) has only 3.9 eV.
Knowing about these trends can help us guess how elements will behave in chemical reactions. Reactivity, electronegativity, and ionization energy are important in creating compounds, understanding how bonds form, and figuring out the stability of molecules during reactions.