1. First 20 Elements Of Periodic Table
2. Element With 20 Atomic Number
3. Periodic Table Of Elements 1 20

First 20 Elements Of Periodic Table

Study State the Atomic Number and Mass Number of First 20 Elements of P.T Flashcards Flashcards at ProProfs - Can you state the atomic number and mass number of first 20 elements of P.T.? If you are confused, these flashcards can help you to understand better. While the mass quantity is the sum of the protons and neutrons in an atom, the atomic number is the value found associated with an. The atomic number of an element 'X' is 20. I)Determine the position of the element 'X' in the periodic table. Ii) Write the formula of the compound formed when 'X' reacts/combines with another element 'Y'(atomic number 8) iii) What would be the nature (acidic or basic) of the compound formed?Justify your answer. The atomic number of an element is equal to the total number of protons in the nucleus of the atoms of that element. The atomic number can provide insight into the electronic configuration of the element. For example, carbon has an electron configuration of He 2s 2 2p 2, since its atomic number is 6. Electron arrangement of the first 20 elements. The table below shows the electron arrangement for the first 20 elements in the Periodic Table along with their Atomic number and symbols.

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SEENotes at the bottom of the Table.

Notes:
• Density of elements with boiling points below 0°C is given in g/l. In a sorted list, these elements are shown before other elements that have boiling points >0°C.
• Earth crust composition average values are from a report by F. W. Clarke and H. S. Washington, 1924. Elemental composition of crustal rocks differ between different localities (see article).
• Group: There are only 18 groups in the periodic table that constitute the columns of the table. Lanthanoids and Actinoids are numbered as 101 and 102 to separate them in sorting by group.
• The elements marked with an asterisk (in the 2nd column) have no stable nuclides. For these elements the weight value shown represents the mass number of the longest-lived isotope of the element.

Abbreviations and Definitions:

No. - Atomic Number; M.P. - melting point; B.P. - boiling point

Atomic number: The number of protons in an atom. Each element is uniquely defined by its atomic number.

Atomic mass: The mass of an atom is primarily determined by the number of protons and neutrons in its nucleus. Atomic mass is measured in Atomic Mass Units (amu) which are scaled relative to carbon, ¹²C, that is taken as a standard element with an atomic mass of 12. This isotope of carbon has 6 protons and 6 neutrons. Thus, each proton and neutron has a mass of about 1 amu.

Isotope: Atoms of the same element with the same atomic number, but different number of neutrons. Isotope of an element is defined by the sum of the number of protons and neutrons in its nucleus. Elements have more than one isotope with varying numbers of neutrons. For example, there are two common isotopes of carbon, ¹²C and ¹³C which have 6 and 7 neutrons respectively. The abundances of different isotopes of elements vary in nature depending on the source of materials. For relative abundances of isotopes in nature see reference on Atomic Weights and Isotopic Compositions.

Element With 20 Atomic Number

Atomic weight: Atomic weight values represent weighted average of the masses of all naturally occurring isotopes of an element. The values shown here are based on the IUPAC Commission determinations (Pure Appl. Chem. 73:667-683, 2001). The elements marked with an asterisk have no stable nuclides. For these elements the weight value shown represents the mass number of the longest-lived isotope of the element.

Electron configuration: See next page for explanation of electron configuration of atoms.

Ionization energy (IE): The energy required to remove the outermost electron from an atom or a positive ion in its ground level. The table lists only the first IE in eV units. To convert to kJ/mol multiply by 96.4869. Reference: NIST Reference Table on Ground states and ionization energies for the neutral atoms. IE decreases going down a column of the periodic table, and increases from left to right in a row. Thus, alkali metals have the lowest IE in a period and Rare gases have the highest.

Other resources related to the Periodic Table

• Chemical Evolution of the Universe
  

List of first 50 elements of the periodic table by atomic number including the chemical symbol and the atomic weight. You can print the list of elements by hitting the print button below.

Periodic Table Of Elements 1 20