Answer:
E. potassium (K) and bromine (Br)
Explanation:
An ionic bond is formed between compounds with a large electronegativity difference between them. It is usually between a metal and non-metal.
- Potassium is a true metal found in group 1 on the periodic table.
- Bromine is a highly electronegative non-metal which is a halogen.
- Potassium will lose one of its electrons which will be gained by the Bromine.
- The electrostatic attraction between the two species will cause the ionic bond to form.
- The ability of one specie willing to lose electron and the other gaining, is the main bed rock of ionic bonding.
Answer: C: experimentation is the best way to obtain knowledge
Explanation: When experimenting you will learn new things and better understand things from it.
Answer: Rutherford.
Explanation:
It was the scientist Ernest Rutherford who, by 1911, performed the gold foil experiment in which α particles were shoot to a thin foild of gold.
That experiment showed that although most α particles passed through the thin gold foild, some of them were deviated in small angles and some other were bounced backward.
The conclusion of the experiment was that the atom contained a small dense positively charged nucleous and negative particles (electrons) surroundiing the nucleous. Being the space in between the nucleous and the electrons empty.
Before Rutherford's experiment the model of the atom was that of the plum pudding presented by J.J Thomson, in which the atom was a solid positively charged sphere with embeded negative charge uniformly distributed in it.
Answer : The correct option is, Subscript numbers tell us how many of the element to their upper-left there are in the molecule.
Explanation :
Subscript number : It indicates that the total number of atoms of an element present in a molecule.
While witting a chemical formula, first we have to write the symbol of an element and then write the number in the bottom of the symbol.
For example :
is the chemical formula of the glucose molecule. The glucose molecule is made up of six carbon atoms, twelve hydrogen atoms and 6 oxygen atoms.
The number 6 of carbon atom is written after and in the bottom (lower-right) of the symbol of carbon element (C). Similarly, the number 12 is written lower-right of the symbol of hydrogen element (H) and the number 6 is written lower-right of the symbol of oxygen element (O).
Therefore, the subscript numbers tell us how many of the element to their upper-left there are in the molecule.
Answer:
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- <em>The halogens posses </em><u><em>seven </em></u><em>valence electrons</em>
Explanation:
- <em>Valence electrons </em>are the electrons in the outermost orbitals of the atoms, which are the orbitals with the highest main energy level (principal quantum number).
- Halogens are the elements of the group 17 of the periodic table: F, Cl, Br, I, At.
- You can tell the number of valence electrons of the representative elements from the number of the group to which they belong. For the representative elements, the number of valence electrons equal the unit digit of the group number.
This table summarizes it:
Group number number of valence electrons
1 1
2 2
13 3
14 4
15 5
16 6
17 7
18 8
- So, in conclusion, <em>the halogens possess 7 valence electrons.</em>
