When moving across a period from left to right in the periodic table, excluding transitions elements, which trend occurs? (1 point)
A. Valence electrons increase by one.
B. The energy levels decrease by one.
C. The energy level increases by one.
D. valence electrons decrease by one.
Valence electrons increase by one
Aoki is correct
Dude is correct
bro is correct
poor dr.bob was just tryna explain lmao
To determine the trend when moving across a period from left to right in the periodic table, we need to understand the arrangement of elements.
In a period, the atomic number increases from left to right, which means the number of protons (and electrons) in the nucleus of the atoms increases. The valence electrons, which are the outermost electrons involved in chemical bonding, are the main focus when determining the trend.
So, let's consider each option and see which one aligns with the trend:
A. Valence electrons increase by one.
This option means that, as you move across a period, each element gains one additional valence electron. However, this is incorrect. The number of valence electrons does not increase by a consistent factor as you move across a period.
B. The energy levels decrease by one.
This option suggests that the energy levels decrease by one as you move from left to right. However, this is also incorrect. The energy levels, which represent different electron shells or orbitals, do not consistently decrease across a period.
C. The energy level increases by one.
This option is closer to the correct answer. As you move from left to right across a period, the energy level (electron shell) increases by one. The electrons are filling higher energy levels, which are further from the nucleus.
D. Valence electrons decrease by one.
This option suggests that each element loses one valence electron as you move across a period. However, this is incorrect. Valence electrons may increase or decrease depending on the specific element.
Therefore, the correct answer is:
C. The energy level increases by one.
As you move across a period from left to right in the periodic table, the energy level (electron shell) of the elements increases by one. This trend occurs until reaching a transition element.
Let's look at the number of electrons in the element beginning with Li and moving to Ne in period 2.
Li = 1; Be = 2; B = 3; C = 4; N = 5; O = 6; F = 7; Ne = 8
What about beginning with H and ending with He in period 1.
H = 1; He = 2
What about period 3 beginning with Na and ending with Ar
Na = 1; Mg = 2; Al = 3; Si = 4; P = 5; S = 6; Cl = 7; Ar = 8
So what do you think?