Try these on your own and check the answer below 78 Se 2-39 K + ANSWERS. ... Mass number and Atomic mass: Mass number is the sum of the number of protons and the number of neutrons present in an atom. We have Provided Structure of the Atom Class 9 Science MCQs Questions with Answers to help students understand the concept very well. (a) What is its atomic number? For example, silicon has 14 protons and 14 neutrons. The sum of protons and electrons in an atom. Most helium atoms have two neutrons in addition to two protons. Figure 2.1.1 A depiction of a helium atom. In an atom, number of protons = number of electrons. It is a whole number. Total number of protons in the nucleus is called the atomic number of the atom and is given the symbol Z.The total electrical charge of the nucleus is therefore +Ze, where e (elementary charge) equals to 1,602 x 10-19 coulombs. - 16 (c) What element is it? An … An atom has 15 protons and has a mass number of 31. Q. all matter is made of what . Its atomic number is 14 and its atomic mass is 28. - 15 (b) How many neutrons does it have? Additional Practice. A helium atom is depicted on Figure 2.1.1. 30 seconds . 30 seconds . Because electrons have virtually no mass, just about all the mass of an atom is in its protons and neutrons. The most common isotope of uranium has 92 protons and 146 neutrons. Atomic # = 17 – 37 = 20 7. SURVEY . ... b. Which statement is not true for an electrochemical cell? You can refer to NCERT Solutions for Class 9 Science Chapter 4 Structure of the Atom to revise the concepts in the syllabus effectively and improve your chances of securing high marks in your board exams. B) 35 protons and 46 neutrons. Mass number is 46 (20 + 26) since mass number is simply the sum of protons and neutrons. Report an issue . C) 46 protons and 35 neutrons. – phosphorus 6. An isotope of an element has a different number of protons from the original element. SURVEY . The sum of protons and neutrons in an atom. Atomic number is 20 since that is simply the number of protons. Hence, the net charge present in an atom is zero i.e. Therefore, the total number of protons and neutrons in an atom determines its mass in atomic mass units (Table \(\PageIndex{1}\)). a free atom is chargeless. Two atoms respectively have Z = 15, A = 30 and Z = 14, A = 30. # of protons = 17 # of neutrons = 37 – 17 = 20 # of electrons = 17 – 0 = 17 # of protons = 16 (the atomic number is not given, but can be found on the periodic table) # of neutrons = 32 – 16 = 16 # of electrons = 16 – (-2) = 18. Question 20 . D) 81 protons and 35 neutrons. The neutron is a subatomic particle, symbol n or n 0, which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton.Protons and neutrons constitute the nuclei of atoms.Since protons and neutrons behave similarly within the nucleus, and each has a mass of approximately one atomic mass unit, they are both referred to as nucleons. Ungraded . A single atom of an element has 21 neutrons, 20 electrons, and 20 protons, which elementis it? 20 14) 10) The isotope symbol for an ion that has 13 protons, 14 neutrons, and 10 electrons is: A) 27 B) Al 13 15 6) The number of protons and neutrons in an atom of bromine-81 is: 14 13 A) 35 protons and 81 neutrons. The element with 14 protons and 14 neutrons is silicon 28 . Ungraded . Its atomic number is 92 and its atomic mass is 238 (92 + 146). Report an issue . https://www.wikihow.com/Find-the-Number-of-Protons,-Neutrons,-and-Electrons Q. Protons and Neutrons in Carbon. How many neutrons can be found in the nucleus of an atom of chlorine-37? Carbon is a chemical element with atomic number 6 which means there are 6 protons in its nucleus. Consider helium again. Question 14 .