| A Russian chemist credited with the creation of the periodic table of elements. | Dmitri Mendeleev. |
| Who is credited with successfully arranging the elements into the first periodic table? | Dmitri Mendeleev. |
| A tabular arrangement of the chemical elements, ordered by their atomic number, electron configuration, and recurring chemical properties. | Periodic Table |
| Why was Mendeleev's arrangement of elements called the periodic table? | It was called the periodic table because it showed recurring patterns or periodic trends in the properties of the elements. |
| The average mass of an element's isotopes relative to the mass of a carbon-12 atom, which is assigned a mass of exactly 12 atomic mass units. | Relative Atomic Mass |
| How did Mendeleev initially arrange the elements in his periodic table? | Mendeleev arranged the elements in order of their relative atomic masses. |
| Regular and repeating trends or patterns in the properties of elements within the periodic table. | Periodic Patterns |
| What allowed Mendeleev to arrange the elements into groups with similar properties? | Periodic patterns in the properties of the elements allowed Mendeleev to group them together based on similarities. |
| Atoms of the same element that have the same number of protons but different numbers of neutrons, leading to variations in atomic mass. | Isotopes |
| How did the discovery of isotopes impact Mendeleev's arrangement of elements? | The discovery of isotopes explained discrepancies in Mendeleev's arrangement based solely on atomic masses, as isotopes can have different masses despite being the same element. |
| The average mass of the atoms of an element, taking into account the masses of all its isotopes and their relative abundances. | Atomic Masses |
| Why did Mendeleev sometimes switch the order of elements in his periodic table? | Mendeleev switched the order if it didn't align with the observed patterns in the elements' properties, which sometimes occurred due to variations in atomic masses caused by isotopes. |
| The relative proportions of different isotopes of an element found in nature. | Isotope Abundances |
| How did isotopic abundances affect the accuracy of Mendeleev's arrangement of elements based on atomic masses? | Isotopic abundances impacted the accuracy because atomic masses were averages of all isotopes, leading to discrepancies in the positioning of elements with abundant heavier isotopes. |
| Values calculated by summing up a set of numbers and dividing the sum by the count of those numbers. | Averages |
| Why did some elements, like tellurium, appear to have higher atomic masses than expected based on their position in the periodic table? | Some elements had abundant heavier isotopes, which increased their average atomic masses and caused discrepancies in their positioning in the periodic table. |
| The arrangement of elements within the periodic table based on their properties and atomic characteristics. | Element Positioning |
| How did Mendeleev's periodic table adaptation accommodate variations in atomic masses caused by isotopes? | Mendeleev adjusted the positioning of elements to better align with observed properties, even if it meant deviating from strict order by atomic mass, which was later understood to be influenced by isotopic abundances. |
| A Russian chemist credited with the creation of the periodic table of elements. | Dmitri Mendeleev. |
| Who is credited with using his periodic table to predict the existence of undiscovered elements? | Dmitri Mendeleev. |
| A periodic table that does not include all known elements at the time of its creation. | Incomplete Periodic Table |
| Why was Mendeleev's periodic table incomplete when he first produced it? | Some elements had not been discovered yet. |
| Spaces deliberately left vacant in the periodic table to accommodate undiscovered elements. | Gaps in the Periodic Table |
| How did Mendeleev address the issue of incomplete knowledge of elements in his periodic table? | Mendeleev left gaps in his periodic table and predicted the existence and properties of undiscovered elements. |
| The ability to forecast or anticipate future events or phenomena based on existing knowledge or patterns. | Predictive Power |
| What strategy did Mendeleev use to predict the properties of undiscovered elements? | Mendeleev utilized patterns in known elements and their properties to predict the properties of undiscovered elements. |
| The process of verifying or validating predictions made based on existing theories or models. | Confirmation of Predictions |
| How were Mendeleev's predictions confirmed? | The elements predicted by Mendeleev were later discovered, and their properties matched his predictions, confirming his ideas. |
| The identification and isolation of previously unknown chemical elements. | New Element Discoveries |
| What role did the discovery of new elements play in confirming Mendeleev's predictions? | The discovery of new elements validated Mendeleev's predictions and supported the accuracy of his periodic table model. |
| A version of the periodic table that arranges elements in order of increasing atomic number. | Modern Periodic Table |
| How are elements arranged in a modern periodic table? | Elements are arranged by their atomic number. |
| The number of protons in the nucleus of an atom, which determines the chemical properties of an element. | Atomic Number |
| What property of elements determines their position in a modern periodic table? | The atomic number. |
| Vertical columns in the periodic table where elements with similar properties are found. | Groups |
| What are the vertical columns in the periodic table called, and what do they represent? | They are called groups, and they represent elements with similar properties. |
| Horizontal rows in the periodic table. | Periods |
| What are the horizontal rows in the periodic table called? | Periods. |
| Elements with properties such as conductivity, malleability, and the tendency to form positive ions. | Metals |
| Where are metals typically found on the periodic table? | Metals are found towards the left-hand side and bottom of the periodic table. |
| Elements with properties such as poor conductivity and the tendency to gain electrons in chemical reactions. | Non-metals |
| Where are non-metals typically found on the periodic table? | Non-metals are found towards the right-hand side and top of the periodic table. |
| Characteristics of substances that can be observed or measured without changing their chemical composition. | Physical Properties |
| What are some typical physical properties of metals? | Conductivity, malleability, and the formation of positive ions. |
| Atoms that have lost one or more electrons, resulting in a net positive charge. | Positive Ions |
| What distinguishes metals from non-metals in terms of ion formation? | Metals can form positive ions, while non-metals do not typically form positive ions. |
