Chemistry - Atom stuff 0.0 / 5 ? ChemistryAtomsNational 5SQA Created by: KalitiseCreated on: 08-10-18 19:17 what does an atom being neutral tell you about the protons and electrons? The number of protons and electrons are the same. 1 of 17 what is the top number? 7/3Li The mass number. 2 of 17 What is the bottom number? 7/3 Li The atomic number. 3 of 17 What the atomic number tell you about an atom? The atomic number tells you the number of protons. 4 of 17 What does the mass number tell you? The number of protons and neutrons. 5 of 17 How do you find the number of neutrons in atom? The atomic number minus the mass number. 6 of 17 How do you find the valency of an element? You look at the group number of the element. Up until group 4, the valencys go up to 4. After 4, they go down to valency 0 at group 8. 7 of 17 What does Mono mean? There is one atom of that element in the molecule. 8 of 17 What does di mean? There are two atoms of that element in the molecule. 9 of 17 What does tri mean? There are three atoms of that element in the molecule. 10 of 17 What does tetra mean? There are four atoms of that element in the molecule. 11 of 17 What does penta mean? There are five atoms of that element in the molecule. 12 of 17 Recite the first five prefixes for molecules. Mono, di, tri, tetra, penta. 13 of 17 How do you find the number of electrons in an atom? The same as finding the number of neutrons - mass number minus the atomic number. 14 of 17 If in a name of a substance, a prefix is shown how do you write the chemical formula? Because it has the prefix, you don't use the valency you just the formula out literally as it says (including the prefix number obviously) 15 of 17 If the name of a substance, no prefixes are used, how do you write the chemical formula? You do the valency cross over method. - Putting the valencys of each element above them, crossing them over and simplifying where possible. 16 of 17 Why is an atom neutral? Because there are equal numbers of positive and negative charges cancel each other out. 17 of 17
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