That is just how it works. A triangle contains 180 degrees, in an equilateral triangle each angle is 60 degrees. For a tetrahedral it just works out to 109.5.
The following explanation should be intelligible if you draw all the figures.
The easiest way to compute this is to start with a cube with length of side = 1. By drawing lines from the centre of the cube to every other corner, we find we have four lines with equal angles between them; thus, these angles are the tetragonal angles we are interested in.
Consider one face of a cube, and draw a line dividing it in half from corner to corner. This forms two right-angled triangles. The hypotenuse of these, by Pythagoras' theorem, is sqrt(2).
Now construct a rectangle by using two edges of the cube, and two face diagonals. The centre of this rectangle is the centre of the cube, and the sides of the rectangle are 1, 1, sqrt(2), sqrt(2). Draw the diagonals. Compare this shape with the cube. The larger angle formed at the centre between the diagonals is the tetrahedral angle, which we will label A.
Now draw one more line, dividing this tetragonal angle into two. This divides two of the triangles in our figure into pairs of right-angled triangles, each having as one angle A/2. The side opposite to A/2 is now sqrt(2)/2, and the adjacent side is 1/2. Thus tan(A/2) = sqrt(2), meaning that A=2*arctan(sqrt(2)), which is approximately 109.47 degrees.
In a tetrahedral molecule the characteristic angle between atoms is 109,5 degrees.
Do i look like einstein
The four electron pairs form a basically tetrahedral shape, but with the angles between the bond pairs slightly smaller than the bond pair to lone pair angle. Ammonia has this shape and the HNH angle is 107 degrees. If you only consider the atoms the shape is called trigonal pyramidal.
Right angle (90) Acute angle (<90) Obtuse angle (>90) Straight angle (180) Reflex angle (>180)
A right angle.
In a tetrahedral molecule the characteristic angle between atoms is 109,5 degrees.
The bond angle in a tetrahedral molecular geometry is approximately 109.5 degrees.
The sulfate ion is tetrahedral, bond angle around 109 0
A tetrahedral molecule will have a 109.5 degree bond angle.
NH4+ is tetrahedral, with bond angle of 109.5o
The shape of the sulfate ion is tetrahedral and the bond angle between the oxygen atoms is approximately 109.5 degrees.
The bond angle in CCl4 is 109.5°. This is because the molecule adopts a tetrahedral geometry, where the bond angles between the carbon atom and the four chlorine atoms are all equal due to the repulsion between electron pairs.
109.5
The CH4 Bond Angle Will Be 109.5 Degrees Because It Has a Tetrahedral Molecular Geometry.
The strain theory is a state of deviation from bond angle of a normal tetrahedral angle.
The bond angle in CH4 (methane) is approximately 109.5 degrees. This is because methane has a tetrahedral molecular geometry with the four hydrogen atoms positioned as far apart from each other as possible.
The H-N-H bond angle (assuming that's what the question is trying to ask) is a bit less than the tetrahedral angle, 109.5o.